summaryrefslogtreecommitdiffstats
path: root/samples (follow)
Commit message (Collapse)AuthorAgeFilesLines
* kfifo: clean up example to not use page_linkLogan Gunthorpe2017-07-131-4/+4
| | | | | | | | | | | | | | | This is a layering violation so we replace the uses with calls to sg_page(). This is a prep patch for replacing page_link and this is one of the very few uses outside of scatterlist.h. Link: http://lkml.kernel.org/r/1495663199-22234-1-git-send-email-logang@deltatee.com Signed-off-by: Logan Gunthorpe <logang@deltatee.com> Signed-off-by: Stephen Bates <sbates@raithlin.com> Acked-by: Stefani Seibold <stefani@seibold.net> Cc: Stefani Seibold <stefani@seibold.net> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* bpf: fix return in load_bpf_fileLawrence Brakmo2017-07-051-2/+6
| | | | | | | | | | | | | | | The function load_bpf_file ignores the return value of load_and_attach(), so even if load_and_attach() returns an error, load_bpf_file() will return 0. Now, load_bpf_file() can call load_and_attach() multiple times and some can succeed and some could fail. I think the correct behavor is to return error on the first failed load_and_attach(). v2: Added missing SOB Signed-off-by: Lawrence Brakmo <brakmo@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: Sample bpf program to set sndcwnd clampLawrence Brakmo2017-07-022-0/+103
| | | | | | | | | | | | Sample BPF program, tcp_clamp_kern.c, to demostrate the use of setting the sndcwnd clamp. This program assumes that if the first 5.5 bytes of the host's IPv6 addresses are the same, then the hosts are in the same datacenter and sets sndcwnd clamp to 100 packets, SYN and SYN-ACK RTOs to 10ms and send/receive buffer sizes to 150KB. Signed-off-by: Lawrence Brakmo <brakmo@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: Sample BPF program to set initial cwndLawrence Brakmo2017-07-022-0/+89
| | | | | | | | | | | | Sample BPF program that assumes hosts are far away (i.e. large RTTs) and sets initial cwnd and initial receive window to 40 packets, send and receive buffers to 1.5MB. In practice there would be a test to insure the hosts are actually far enough away. Signed-off-by: Lawrence Brakmo <brakmo@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: Sample BPF program to set congestion controlLawrence Brakmo2017-07-022-0/+84
| | | | | | | | | Sample BPF program that sets congestion control to dctcp when both hosts are within the same datacenter. In this example that is assumed to be when they have the first 5.5 bytes of their IPv6 address are the same. Signed-off-by: Lawrence Brakmo <brakmo@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: Sample BPF program to set buffer sizesLawrence Brakmo2017-07-022-0/+87
| | | | | | | | | | This patch contains a BPF program to set initial receive window to 40 packets and send and receive buffers to 1.5MB. This would usually be done after doing appropriate checks that indicate the hosts are far enough away (i.e. large RTT). Signed-off-by: Lawrence Brakmo <brakmo@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: Add setsockopt helper function to bpfLawrence Brakmo2017-07-021-0/+3
| | | | | | | | | | | | | | | | | | Added support for calling a subset of socket setsockopts from BPF_PROG_TYPE_SOCK_OPS programs. The code was duplicated rather than making the changes to call the socket setsockopt function because the changes required would have been larger. The ops supported are: SO_RCVBUF SO_SNDBUF SO_MAX_PACING_RATE SO_PRIORITY SO_RCVLOWAT SO_MARK Signed-off-by: Lawrence Brakmo <brakmo@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: Sample bpf program to set initial windowLawrence Brakmo2017-07-022-0/+70
| | | | | | | | | | | The sample bpf program, tcp_rwnd_kern.c, sets the initial advertized window to 40 packets in an environment where distinct IPv6 prefixes indicate that both hosts are not in the same data center. Signed-off-by: Lawrence Brakmo <brakmo@fb.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: Sample bpf program to set SYN/SYN-ACK RTOsLawrence Brakmo2017-07-022-0/+70
| | | | | | | | | | | The sample BPF program, tcp_synrto_kern.c, sets the SYN and SYN-ACK RTOs to 10ms when both hosts are within the same datacenter (i.e. small RTTs) in an environment where common IPv6 prefixes indicate both hosts are in the same data center. Signed-off-by: Lawrence Brakmo <brakmo@fb.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: program to load and attach sock_ops BPF progsLawrence Brakmo2017-07-022-0/+100
| | | | | | | | | | | | | | | | | | | | | | The program load_sock_ops can be used to load sock_ops bpf programs and to attach it to an existing (v2) cgroup. It can also be used to detach sock_ops programs. Examples: load_sock_ops [-l] <cg-path> <prog filename> Load and attaches a sock_ops program at the specified cgroup. If "-l" is used, the program will continue to run to output the BPF log buffer. If the specified filename does not end in ".o", it appends "_kern.o" to the name. load_sock_ops -r <cg-path> Detaches the currently attached sock_ops program from the specified cgroup. Signed-off-by: Lawrence Brakmo <brakmo@fb.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: BPF support for sock_opsLawrence Brakmo2017-07-021-3/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Created a new BPF program type, BPF_PROG_TYPE_SOCK_OPS, and a corresponding struct that allows BPF programs of this type to access some of the socket's fields (such as IP addresses, ports, etc.). It uses the existing bpf cgroups infrastructure so the programs can be attached per cgroup with full inheritance support. The program will be called at appropriate times to set relevant connections parameters such as buffer sizes, SYN and SYN-ACK RTOs, etc., based on connection information such as IP addresses, port numbers, etc. Alghough there are already 3 mechanisms to set parameters (sysctls, route metrics and setsockopts), this new mechanism provides some distinct advantages. Unlike sysctls, it can set parameters per connection. In contrast to route metrics, it can also use port numbers and information provided by a user level program. In addition, it could set parameters probabilistically for evaluation purposes (i.e. do something different on 10% of the flows and compare results with the other 90% of the flows). Also, in cases where IPv6 addresses contain geographic information, the rules to make changes based on the distance (or RTT) between the hosts are much easier than route metric rules and can be global. Finally, unlike setsockopt, it oes not require application changes and it can be updated easily at any time. Although the bpf cgroup framework already contains a sock related program type (BPF_PROG_TYPE_CGROUP_SOCK), I created the new type (BPF_PROG_TYPE_SOCK_OPS) beccause the existing type expects to be called only once during the connections's lifetime. In contrast, the new program type will be called multiple times from different places in the network stack code. For example, before sending SYN and SYN-ACKs to set an appropriate timeout, when the connection is established to set congestion control, etc. As a result it has "op" field to specify the type of operation requested. The purpose of this new program type is to simplify setting connection parameters, such as buffer sizes, TCP's SYN RTO, etc. For example, it is easy to use facebook's internal IPv6 addresses to determine if both hosts of a connection are in the same datacenter. Therefore, it is easy to write a BPF program to choose a small SYN RTO value when both hosts are in the same datacenter. This patch only contains the framework to support the new BPF program type, following patches add the functionality to set various connection parameters. This patch defines a new BPF program type: BPF_PROG_TYPE_SOCKET_OPS and a new bpf syscall command to load a new program of this type: BPF_PROG_LOAD_SOCKET_OPS. Two new corresponding structs (one for the kernel one for the user/BPF program): /* kernel version */ struct bpf_sock_ops_kern { struct sock *sk; __u32 op; union { __u32 reply; __u32 replylong[4]; }; }; /* user version * Some fields are in network byte order reflecting the sock struct * Use the bpf_ntohl helper macro in samples/bpf/bpf_endian.h to * convert them to host byte order. */ struct bpf_sock_ops { __u32 op; union { __u32 reply; __u32 replylong[4]; }; __u32 family; __u32 remote_ip4; /* In network byte order */ __u32 local_ip4; /* In network byte order */ __u32 remote_ip6[4]; /* In network byte order */ __u32 local_ip6[4]; /* In network byte order */ __u32 remote_port; /* In network byte order */ __u32 local_port; /* In host byte horder */ }; Currently there are two types of ops. The first type expects the BPF program to return a value which is then used by the caller (or a negative value to indicate the operation is not supported). The second type expects state changes to be done by the BPF program, for example through a setsockopt BPF helper function, and they ignore the return value. The reply fields of the bpf_sockt_ops struct are there in case a bpf program needs to return a value larger than an integer. Signed-off-by: Lawrence Brakmo <brakmo@fb.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: Add test for syscall on fd array/htab lookupMartin KaFai Lau2017-06-292-1/+31
| | | | | | | | Checks are added to the existing sockex3 and test_map_in_map test. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* samples/bpf: fix a build problemYonghong Song2017-06-221-1/+1
| | | | | | | | | | | | | tracex5_kern.c build failed with the following error message: ../samples/bpf/tracex5_kern.c:12:10: fatal error: 'syscall_nrs.h' file not found #include "syscall_nrs.h" The generated file syscall_nrs.h is put in build/samples/bpf directory, but this directory is not in include path, hence build failed. The fix is to add $(obj) into the clang compilation path. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* pktgen: Specify the index of first threadTariq Toukan2017-06-168-18/+27
| | | | | | | | | | | Use "-f <num>", to specify the index of the first sender thread. In default first thread is #0. Signed-off-by: Tariq Toukan <tariqt@mellanox.com> Cc: Jesper Dangaard Brouer <brouer@redhat.com> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* pktgen: Specify num packets per threadTariq Toukan2017-06-169-8/+15
| | | | | | | | | | | Use -n <num>, to specify the number of packets every thread sends. Zero means indefinitely. Signed-off-by: Tariq Toukan <tariqt@mellanox.com> Cc: Jesper Dangaard Brouer <brouer@redhat.com> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* samples/bpf: Fix tracex5 to work with MIPS syscalls.David Daney2017-06-143-3/+33
| | | | | | | | | | | | | | | | | | | | | | | | | | | | There are two problems: 1) In MIPS the __NR_* macros expand to an expression, this causes the sections of the object file to be named like: . . . [ 5] kprobe/(5000 + 1) PROGBITS 0000000000000000 000160 ... [ 6] kprobe/(5000 + 0) PROGBITS 0000000000000000 000258 ... [ 7] kprobe/(5000 + 9) PROGBITS 0000000000000000 000348 ... . . . The fix here is to use the "asm_offsets" trick to evaluate the macros in the C compiler and generate a header file with a usable form of the macros. 2) MIPS syscall numbers start at 5000, so we need a bigger map to hold the sub-programs. Signed-off-by: David Daney <david.daney@cavium.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: Add MIPS support to samples/bpf.David Daney2017-06-141-0/+13
| | | | | | Signed-off-by: David Daney <david.daney@cavium.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* samples/bpf: add tests for more perf event typesTeng Qin2017-06-054-56/+228
| | | | | | | | | | | | | | | | | | | $ trace_event tests attaching BPF program to HW_CPU_CYCLES, SW_CPU_CLOCK, HW_CACHE_L1D and other events. It runs 'dd' in the background while bpf program collects user and kernel stack trace on counter overflow. User space expects to see sys_read and sys_write in the kernel stack. $ tracex6 tests reading of various perf counters from BPF program. Both tests were refactored to increase coverage and be more accurate. Signed-off-by: Teng Qin <qinteng@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* samples/bpf: bpf_load.c order of prog_fd[] should correspond with ELF orderJesper Dangaard Brouer2017-05-311-14/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | An eBPF ELF file generated with LLVM can contain several program section, which can be used for bpf tail calls. The bpf prog file descriptors are accessible via array prog_fd[]. At-least XDP samples assume ordering, and uses prog_fd[0] is the main XDP program to attach. The actual order of array prog_fd[] depend on whether or not a bpf program section is referencing any maps or not. Not using a map result in being loaded/processed after all other prog section. Thus, this can lead to some very strange and hard to debug situation, as the user can only see a FD and cannot correlated that with the ELF section name. The fix is rather simple, and even removes duplicate memcmp code. Simply load program sections as the last step, instead of load_and_attach while processing the relocation section. When working with tail calls, it become even more essential that the order of prog_fd[] is consistant, like the current dependency of the map_fd[] order. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* samples/bpf: run cleanup routines when receiving SIGTERMAndy Gospodarek2017-05-127-1/+9
| | | | | | | | | | | | | | | | Shahid Habib noticed that when xdp1 was killed from a different console the xdp program was not cleaned-up properly in the kernel and it continued to forward traffic. Most of the applications in samples/bpf cleanup properly, but only when getting SIGINT. Since kill defaults to using SIGTERM, add support to cleanup when the application receives either SIGINT or SIGTERM. Signed-off-by: Andy Gospodarek <andy@greyhouse.net> Reported-by: Shahid Habib <shahid.habib@broadcom.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* xdp: add flag to enforce driver modeDaniel Borkmann2017-05-122-3/+12
| | | | | | | | | | | | After commit b5cdae3291f7 ("net: Generic XDP") we automatically fall back to a generic XDP variant if the driver does not support native XDP. Allow for an option where the user can specify that always the native XDP variant should be selected and in case it's not supported by a driver, just bail out. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* Merge tag 'char-misc-4.12-rc1' of ↵Linus Torvalds2017-05-051-2/+0
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc Pull char/misc driver updates from Greg KH: "Here is the big set of new char/misc driver drivers and features for 4.12-rc1. There's lots of new drivers added this time around, new firmware drivers from Google, more auxdisplay drivers, extcon drivers, fpga drivers, and a bunch of other driver updates. Nothing major, except if you happen to have the hardware for these drivers, and then you will be happy :) All of these have been in linux-next for a while with no reported issues" * tag 'char-misc-4.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (136 commits) firmware: google memconsole: Fix return value check in platform_memconsole_init() firmware: Google VPD: Fix return value check in vpd_platform_init() goldfish_pipe: fix build warning about using too much stack. goldfish_pipe: An implementation of more parallel pipe fpga fr br: update supported version numbers fpga: region: release FPGA region reference in error path fpga altera-hps2fpga: disable/unprepare clock on error in alt_fpga_bridge_probe() mei: drop the TODO from samples firmware: Google VPD sysfs driver firmware: Google VPD: import lib_vpd source files misc: lkdtm: Add volatile to intentional NULL pointer reference eeprom: idt_89hpesx: Add OF device ID table misc: ds1682: Add OF device ID table misc: tsl2550: Add OF device ID table w1: Remove unneeded use of assert() and remove w1_log.h w1: Use kernel common min() implementation uio_mf624: Align memory regions to page size and set correct offsets uio_mf624: Refactor memory info initialization uio: Allow handling of non page-aligned memory regions hangcheck-timer: Fix typo in comment ...
| * mei: drop the TODO from samplesTomas Winkler2017-04-261-2/+0
| | | | | | | | | | | | | | | | | | The TODO file is not relevant anymore and it's just a leftover from the time the driver was in the staging tree. Signed-off-by: Tomas Winkler <tomas.winkler@intel.com> Reviewed-by: Alexander Usyskin <alexander.usyskin@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | samples/bpf: export map_data[] for more info on mapsJesper Dangaard Brouer2017-05-031-1/+7
| | | | | | | | | | | | | | | | | | | | | | | | Giving *_user.c side tools access to map_data[] provides easier access to information on the maps being loaded. Still provide the guarantee that the order maps are being defined in inside the _kern.c file corresponds with the order in the array. Now user tools are not blind, but can inspect and verify the maps that got loaded from the ELF binary. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | samples/bpf: load_bpf.c make callback fixup more flexibleJesper Dangaard Brouer2017-05-033-18/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Do this change before others start to use this callback. Change map_perf_test_user.c which seems to be the only user. This patch extends capabilities of commit 9fd63d05f3e8 ("bpf: Allow bpf sample programs (*_user.c) to change bpf_map_def"). Give fixup callback access to struct bpf_map_data, instead of only stuct bpf_map_def. This add flexibility to allow userspace to reassign the map file descriptor. This is very useful when wanting to share maps between several bpf programs. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | samples/bpf: make bpf_load.c code compatible with ELF maps section changesJesper Dangaard Brouer2017-05-031-69/+155
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch does proper parsing of the ELF "maps" section, in-order to be both backwards and forwards compatible with changes to the map definition struct bpf_map_def, which gets compiled into the ELF file. The assumption is that new features with value zero, means that they are not in-use. For backward compatibility where loading an ELF file with a smaller struct bpf_map_def, only copy objects ELF size, leaving rest of loaders struct zero. For forward compatibility where ELF file have a larger struct bpf_map_def, only copy loaders own struct size and verify that rest of the larger struct is zero, assuming this means the newer feature was not activated, thus it should be safe for this older loader to load this newer ELF file. Fixes: fb30d4b71214 ("bpf: Add tests for map-in-map") Fixes: 409526bea3c3 ("samples/bpf: bpf_load.c detect and abort if ELF maps section size is wrong") Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* | samples/bpf: adjust rlimit RLIMIT_MEMLOCK for traceex2, tracex3 and tracex4Jesper Dangaard Brouer2017-05-033-0/+22
| | | | | | | | | | | | | | | | Needed to adjust max locked memory RLIMIT_MEMLOCK for testing these bpf samples as these are using more and larger maps than can fit in distro default 64Kbytes limit. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | Merge branch 'for-linus' of ↵Linus Torvalds2017-05-031-1/+17
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching Pull livepatch updates from Jiri Kosina: - a per-task consistency model is being added for architectures that support reliable stack dumping (extending this, currently rather trivial set, is currently in the works). This extends the nature of the types of patches that can be applied by live patching infrastructure. The code stems from the design proposal made [1] back in November 2014. It's a hybrid of SUSE's kGraft and RH's kpatch, combining advantages of both: it uses kGraft's per-task consistency and syscall barrier switching combined with kpatch's stack trace switching. There are also a number of fallback options which make it quite flexible. Most of the heavy lifting done by Josh Poimboeuf with help from Miroslav Benes and Petr Mladek [1] https://lkml.kernel.org/r/20141107140458.GA21774@suse.cz - module load time patch optimization from Zhou Chengming - a few assorted small fixes * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching: livepatch: add missing printk newlines livepatch: Cancel transition a safe way for immediate patches livepatch: Reduce the time of finding module symbols livepatch: make klp_mutex proper part of API livepatch: allow removal of a disabled patch livepatch: add /proc/<pid>/patch_state livepatch: change to a per-task consistency model livepatch: store function sizes livepatch: use kstrtobool() in enabled_store() livepatch: move patching functions into patch.c livepatch: remove unnecessary object loaded check livepatch: separate enabled and patched states livepatch/s390: add TIF_PATCH_PENDING thread flag livepatch/s390: reorganize TIF thread flag bits livepatch/powerpc: add TIF_PATCH_PENDING thread flag livepatch/x86: add TIF_PATCH_PENDING thread flag livepatch: create temporary klp_update_patch_state() stub x86/entry: define _TIF_ALLWORK_MASK flags explicitly stacktrace/x86: add function for detecting reliable stack traces
| * | livepatch: allow removal of a disabled patchJosh Poimboeuf2017-03-081-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently we do not allow patch module to unload since there is no method to determine if a task is still running in the patched code. The consistency model gives us the way because when the unpatching finishes we know that all tasks were marked as safe to call an original function. Thus every new call to the function calls the original code and at the same time no task can be somewhere in the patched code, because it had to leave that code to be marked as safe. We can safely let the patch module go after that. Completion is used for synchronization between module removal and sysfs infrastructure in a similar way to commit 942e443127e9 ("module: Fix mod->mkobj.kobj potentially freed too early"). Note that we still do not allow the removal for immediate model, that is no consistency model. The module refcount may increase in this case if somebody disables and enables the patch several times. This should not cause any harm. With this change a call to try_module_get() is moved to __klp_enable_patch from klp_register_patch to make module reference counting symmetric (module_put() is in a patch disable path) and to allow to take a new reference to a disabled module when being enabled. Finally, we need to be very careful about possible races between klp_unregister_patch(), kobject_put() functions and operations on the related sysfs files. kobject_put(&patch->kobj) must be called without klp_mutex. Otherwise, it might be blocked by enabled_store() that needs the mutex as well. In addition, enabled_store() must check if the patch was not unregisted in the meantime. There is no need to do the same for other kobject_put() callsites at the moment. Their sysfs operations neither take the lock nor they access any data that might be freed in the meantime. There was an attempt to use kobjects the right way and prevent these races by design. But it made the patch definition more complicated and opened another can of worms. See https://lkml.kernel.org/r/1464018848-4303-1-git-send-email-pmladek@suse.com [Thanks to Petr Mladek for improving the commit message.] Signed-off-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Acked-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
| * | livepatch: change to a per-task consistency modelJosh Poimboeuf2017-03-081-0/+17
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Change livepatch to use a basic per-task consistency model. This is the foundation which will eventually enable us to patch those ~10% of security patches which change function or data semantics. This is the biggest remaining piece needed to make livepatch more generally useful. This code stems from the design proposal made by Vojtech [1] in November 2014. It's a hybrid of kGraft and kpatch: it uses kGraft's per-task consistency and syscall barrier switching combined with kpatch's stack trace switching. There are also a number of fallback options which make it quite flexible. Patches are applied on a per-task basis, when the task is deemed safe to switch over. When a patch is enabled, livepatch enters into a transition state where tasks are converging to the patched state. Usually this transition state can complete in a few seconds. The same sequence occurs when a patch is disabled, except the tasks converge from the patched state to the unpatched state. An interrupt handler inherits the patched state of the task it interrupts. The same is true for forked tasks: the child inherits the patched state of the parent. Livepatch uses several complementary approaches to determine when it's safe to patch tasks: 1. The first and most effective approach is stack checking of sleeping tasks. If no affected functions are on the stack of a given task, the task is patched. In most cases this will patch most or all of the tasks on the first try. Otherwise it'll keep trying periodically. This option is only available if the architecture has reliable stacks (HAVE_RELIABLE_STACKTRACE). 2. The second approach, if needed, is kernel exit switching. A task is switched when it returns to user space from a system call, a user space IRQ, or a signal. It's useful in the following cases: a) Patching I/O-bound user tasks which are sleeping on an affected function. In this case you have to send SIGSTOP and SIGCONT to force it to exit the kernel and be patched. b) Patching CPU-bound user tasks. If the task is highly CPU-bound then it will get patched the next time it gets interrupted by an IRQ. c) In the future it could be useful for applying patches for architectures which don't yet have HAVE_RELIABLE_STACKTRACE. In this case you would have to signal most of the tasks on the system. However this isn't supported yet because there's currently no way to patch kthreads without HAVE_RELIABLE_STACKTRACE. 3. For idle "swapper" tasks, since they don't ever exit the kernel, they instead have a klp_update_patch_state() call in the idle loop which allows them to be patched before the CPU enters the idle state. (Note there's not yet such an approach for kthreads.) All the above approaches may be skipped by setting the 'immediate' flag in the 'klp_patch' struct, which will disable per-task consistency and patch all tasks immediately. This can be useful if the patch doesn't change any function or data semantics. Note that, even with this flag set, it's possible that some tasks may still be running with an old version of the function, until that function returns. There's also an 'immediate' flag in the 'klp_func' struct which allows you to specify that certain functions in the patch can be applied without per-task consistency. This might be useful if you want to patch a common function like schedule(), and the function change doesn't need consistency but the rest of the patch does. For architectures which don't have HAVE_RELIABLE_STACKTRACE, the user must set patch->immediate which causes all tasks to be patched immediately. This option should be used with care, only when the patch doesn't change any function or data semantics. In the future, architectures which don't have HAVE_RELIABLE_STACKTRACE may be allowed to use per-task consistency if we can come up with another way to patch kthreads. The /sys/kernel/livepatch/<patch>/transition file shows whether a patch is in transition. Only a single patch (the topmost patch on the stack) can be in transition at a given time. A patch can remain in transition indefinitely, if any of the tasks are stuck in the initial patch state. A transition can be reversed and effectively canceled by writing the opposite value to the /sys/kernel/livepatch/<patch>/enabled file while the transition is in progress. Then all the tasks will attempt to converge back to the original patch state. [1] https://lkml.kernel.org/r/20141107140458.GA21774@suse.cz Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Ingo Molnar <mingo@kernel.org> # for the scheduler changes Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* | bpf, samples: fix build warning in cookie_uid_helper_exampleDaniel Borkmann2017-05-021-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix the following warnings triggered by 51570a5ab2b7 ("A Sample of using socket cookie and uid for traffic monitoring"): In file included from /home/foo/net-next/samples/bpf/cookie_uid_helper_example.c:54:0: /home/foo/net-next/samples/bpf/cookie_uid_helper_example.c: In function 'prog_load': /home/foo/net-next/samples/bpf/cookie_uid_helper_example.c:119:27: warning: overflow in implicit constant conversion [-Woverflow] -32 + offsetof(struct stats, uid)), ^ /home/foo/net-next/samples/bpf/libbpf.h:135:12: note: in definition of macro 'BPF_STX_MEM' .off = OFF, \ ^ /home/foo/net-next/samples/bpf/cookie_uid_helper_example.c:121:27: warning: overflow in implicit constant conversion [-Woverflow] -32 + offsetof(struct stats, packets), 1), ^ /home/foo/net-next/samples/bpf/libbpf.h:155:12: note: in definition of macro 'BPF_ST_MEM' .off = OFF, \ ^ /home/foo/net-next/samples/bpf/cookie_uid_helper_example.c:129:27: warning: overflow in implicit constant conversion [-Woverflow] -32 + offsetof(struct stats, bytes)), ^ /home/foo/net-next/samples/bpf/libbpf.h:135:12: note: in definition of macro 'BPF_STX_MEM' .off = OFF, \ ^ HOSTLD /home/foo/net-next/samples/bpf/per_socket_stats_example Fixes: 51570a5ab2b7 ("A Sample of using socket cookie and uid for traffic monitoring") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* | samples/bpf: fix XDP_FLAGS_SKB_MODE detach for xdp_tx_iptunnelJesper Dangaard Brouer2017-05-011-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The xdp_tx_iptunnel program can be terminated in two ways, after N-seconds or via Ctrl-C SIGINT. The SIGINT code path does not handle detatching the correct XDP program, in-case the program was attached with XDP_FLAGS_SKB_MODE. Fix this by storing the XDP flags as a global variable, which is available for the SIGINT handler function. Fixes: 3993f2cb983b ("samples/bpf: Add support for SKB_MODE to xdp1 and xdp_tx_iptunnel") Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Andy Gospodarek <andy@greyhouse.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* | samples/bpf: fix SKB_MODE flag to be a 32-bit unsigned intJesper Dangaard Brouer2017-05-014-10/+11
| | | | | | | | | | | | | | | | | | | | | | | | The kernel side of XDP_FLAGS_SKB_MODE is unsigned, and the rtnetlink IFLA_XDP_FLAGS is defined as NLA_U32. Thus, userspace programs under samples/bpf/ should use the correct type. Fixes: 3993f2cb983b ("samples/bpf: Add support for SKB_MODE to xdp1 and xdp_tx_iptunnel") Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Andy Gospodarek <andy@greyhouse.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* | samples/bpf: bpf_load.c detect and abort if ELF maps section size is wrongJesper Dangaard Brouer2017-05-011-9/+31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The struct bpf_map_def was extended in commit fb30d4b71214 ("bpf: Add tests for map-in-map") with member unsigned int inner_map_idx. This changed the size of the maps section in the generated ELF _kern.o files. Unfortunately the loader in bpf_load.c does not detect or handle this. Thus, older _kern.o files became incompatible, and caused hard-to-debug errors where the syscall validation rejected BPF_MAP_CREATE request. This patch only detect the situation and aborts load_bpf_file(). It also add code comments warning people that read this loader for inspiration for these pitfalls. Fixes: fb30d4b71214 ("bpf: Add tests for map-in-map") Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* | samples/bpf: Add support for SKB_MODE to xdp1 and xdp_tx_iptunnelDavid Ahern2017-04-274-16/+58
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Add option to xdp1 and xdp_tx_iptunnel to insert xdp program in SKB_MODE: - update set_link_xdp_fd to take a flags argument that is added to the RTM_SETLINK message - Add -S option to xdp1 and xdp_tx_iptunnel user code. When passed in XDP_FLAGS_SKB_MODE is set in the flags arg passed to set_link_xdp_fd Signed-off-by: David Ahern <dsa@cumulusnetworks.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* | samples/bpf: check before defining offsetofAlexander Alemayhu2017-04-241-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fixes the following warning samples/bpf/test_lru_dist.c:28:0: warning: "offsetof" redefined #define offsetof(TYPE, MEMBER) ((size_t)&((TYPE *)0)->MEMBER) In file included from ./tools/lib/bpf/bpf.h:25:0, from samples/bpf/libbpf.h:5, from samples/bpf/test_lru_dist.c:24: /usr/lib/gcc/x86_64-redhat-linux/6.3.1/include/stddef.h:417:0: note: this is the location of the previous definition #define offsetof(TYPE, MEMBER) __builtin_offsetof (TYPE, MEMBER) Signed-off-by: Alexander Alemayhu <alexander@alemayhu.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* | samples/bpf: add static to function with no prototypeAlexander Alemayhu2017-04-241-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Fixes the following warning samples/bpf/cookie_uid_helper_example.c: At top level: samples/bpf/cookie_uid_helper_example.c:276:6: warning: no previous prototype for ‘finish’ [-Wmissing-prototypes] void finish(int ret) ^~~~~~ HOSTLD samples/bpf/per_socket_stats_example Signed-off-by: Alexander Alemayhu <alexander@alemayhu.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* | samples/bpf: add -Wno-unknown-warning-option to clangAlexander Alemayhu2017-04-241-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I was initially going to remove '-Wno-address-of-packed-member' because I thought it was not supposed to be there but Daniel suggested using '-Wno-unknown-warning-option'. This silences several warnings similiar to the one below warning: unknown warning option '-Wno-address-of-packed-member' [-Wunknown-warning-option] 1 warning generated. clang -nostdinc -isystem /usr/lib/gcc/x86_64-redhat-linux/6.3.1/include -I./arch/x86/include -I./arch/x86/include/generated/uapi -I./arch/x86/include/generated -I./include -I./arch/x86/include/uapi -I./include/uapi -I./include/generated/uapi -include ./include/linux/kconfig.h \ -D__KERNEL__ -D__ASM_SYSREG_H -Wno-unused-value -Wno-pointer-sign \ -Wno-compare-distinct-pointer-types \ -Wno-gnu-variable-sized-type-not-at-end \ -Wno-address-of-packed-member -Wno-tautological-compare \ -O2 -emit-llvm -c samples/bpf/xdp_tx_iptunnel_kern.c -o -| llc -march=bpf -filetype=obj -o samples/bpf/xdp_tx_iptunnel_kern.o $ clang --version clang version 3.9.1 (tags/RELEASE_391/final) Target: x86_64-unknown-linux-gnu Thread model: posix InstalledDir: /usr/bin Signed-off-by: Alexander Alemayhu <alexander@alemayhu.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* | bpf: Add sparc support to tools and samples.David S. Miller2017-04-221-0/+19
| | | | | | | | | | Signed-off-by: David S. Miller <davem@davemloft.net> Acked-by: Daniel Borkmann <daniel@iogearbox.net>
* | bpf: lru: Add map-in-map LRU exampleMartin KaFai Lau2017-04-172-3/+93
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds a map-in-map LRU example. If we know only a subset of cores will use the LRU, we can allocate a common LRU list per targeting core and store it into an array-of-hashs. It allows using the common LRU map with map-update performance comparable to the BPF_F_NO_COMMON_LRU map but without wasting memory on the unused cores that we know they will never access the LRU map. BPF_F_NO_COMMON_LRU: > map_perf_test 32 8 10000000 10000000 | awk '{sum += $3}END{print sum}' 9234314 (9.23M/s) map-in-map LRU: > map_perf_test 512 8 1260000 80000000 | awk '{sum += $3}END{print sum}' 9962743 (9.96M/s) Notes that the max_entries for the map-in-map LRU test is 1260000 which is the max_entries for each inner LRU map. 8 processes have been started, so 8 * 1260000 = 10080000 (~10M) which is close to what is used in the BPF_F_NO_COMMON_LRU test. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | bpf: Allow bpf sample programs (*_user.c) to change bpf_map_defMartin KaFai Lau2017-04-173-74/+201
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The current bpf_map_def is statically defined during compile time. This patch allows the *_user.c program to change it during runtime. It is done by adding load_bpf_file_fixup_map() which takes a callback. The callback will be called before creating each map so that it has a chance to modify the bpf_map_def. The current usecase is to change max_entries in map_perf_test. It is interesting to test with a much bigger map size in some cases (e.g. the following patch on bpf_lru_map.c). However, it is hard to find one size to fit all testing environment. Hence, it is handy to take the max_entries as a cmdline arg and then configure the bpf_map_def during runtime. This patch adds two cmdline args. One is to configure the map's max_entries. Another is to configure the max_cnt which controls how many times a syscall is called. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* | bpf: lru: Refactor LRU map tests in map_perf_testMartin KaFai Lau2017-04-172-29/+67
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | One more LRU test will be added later in this patch series. In this patch, we first move all existing LRU map tests into a single syscall (connect) first so that the future new LRU test can be added without hunting another syscall. One of the map name is also changed from percpu_lru_hash_map to nocommon_lru_hash_map to avoid the confusion with percpu_hash_map. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* | Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller2017-04-161-4/+8
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts were simply overlapping changes. In the net/ipv4/route.c case the code had simply moved around a little bit and the same fix was made in both 'net' and 'net-next'. In the net/sched/sch_generic.c case a fix in 'net' happened at the same time that a new argument was added to qdisc_hash_add(). Signed-off-by: David S. Miller <davem@davemloft.net>
| * | statx: Include a mask for stx_attributes in struct statxDavid Howells2017-04-031-4/+8
| |/ | | | | | | | | | | | | | | | | | | | | | | Include a mask in struct stat to indicate which bits of stx_attributes the filesystem actually supports. This would also be useful if we add another system call that allows you to do a 'bulk attribute set' and pass in a statx struct with the masks appropriately set to say what you want to set. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | Sample program using SO_COOKIEChenbo Feng2017-04-082-23/+127
| | | | | | | | | | | | | | | | | | | | | | Added a per socket traffic monitoring option to illustrate the usage of new getsockopt SO_COOKIE. The program is based on the socket traffic monitoring program using xt_eBPF and in the new option the data entry can be directly accessed using socket cookie. The cookie retrieved allow us to lookup an element in the eBPF for a specific socket. Signed-off-by: Chenbo Feng <fengc@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | A Sample of using socket cookie and uid for traffic monitoringChenbo Feng2017-03-244-0/+244
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a sample program to demostrate the possible usage of get_socket_cookie and get_socket_uid helper function. The program will store bytes and packets counting of in/out traffic monitored by iptables and store the stats in a bpf map in per socket base. The owner uid of the socket will be stored as part of the data entry. A shell script for running the program is also included. Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Chenbo Feng <fengc@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | bpf: Add tests for map-in-mapMartin KaFai Lau2017-03-225-5/+311
| | | | | | | | | | | | | | | | Test cases for array of maps and hash of maps. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* | samples/bpf: add map_lookup microbenchmarkAlexei Starovoitov2017-03-172-0/+65
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | $ map_perf_test 128 speed of HASH bpf_map_lookup_elem() in lookups per second w/o JIT w/JIT before 46M 58M after 42M 74M perf report before: 54.23% map_perf_test [kernel.kallsyms] [k] __htab_map_lookup_elem 14.24% map_perf_test [kernel.kallsyms] [k] lookup_elem_raw 8.84% map_perf_test [kernel.kallsyms] [k] htab_map_lookup_elem 5.93% map_perf_test [kernel.kallsyms] [k] bpf_map_lookup_elem 2.30% map_perf_test [kernel.kallsyms] [k] bpf_prog_da4fc6a3f41761a2 1.49% map_perf_test [kernel.kallsyms] [k] kprobe_ftrace_handler after: 60.03% map_perf_test [kernel.kallsyms] [k] __htab_map_lookup_elem 18.07% map_perf_test [kernel.kallsyms] [k] lookup_elem_raw 2.91% map_perf_test [kernel.kallsyms] [k] bpf_prog_da4fc6a3f41761a2 1.94% map_perf_test [kernel.kallsyms] [k] _einittext 1.90% map_perf_test [kernel.kallsyms] [k] __audit_syscall_exit 1.72% map_perf_test [kernel.kallsyms] [k] kprobe_ftrace_handler Notice that bpf_map_lookup_elem() and htab_map_lookup_elem() are trivial functions, yet they take sizeable amount of cpu time. htab_map_gen_lookup() removes bpf_map_lookup_elem() and converts htab_map_lookup_elem() into three BPF insns which causing cpu time for bpf_prog_da4fc6a3f41761a2() slightly increase. $ map_perf_test 256 speed of ARRAY bpf_map_lookup_elem() in lookups per second w/o JIT w/JIT before 97M 174M after 64M 280M before: 37.33% map_perf_test [kernel.kallsyms] [k] array_map_lookup_elem 13.95% map_perf_test [kernel.kallsyms] [k] bpf_map_lookup_elem 6.54% map_perf_test [kernel.kallsyms] [k] bpf_prog_da4fc6a3f41761a2 4.57% map_perf_test [kernel.kallsyms] [k] kprobe_ftrace_handler after: 32.86% map_perf_test [kernel.kallsyms] [k] bpf_prog_da4fc6a3f41761a2 6.54% map_perf_test [kernel.kallsyms] [k] kprobe_ftrace_handler array_map_gen_lookup() removes calls to array_map_lookup_elem() and bpf_map_lookup_elem() and replaces them with 7 bpf insns. The performance without JIT is slower, since executing extra insns in the interpreter is slower than running native C code, but with JIT the performance gains are obvious, since native C->x86 code is replaced with fewer bpf->x86 instructions. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* Merge branch 'rebased-statx' of ↵Linus Torvalds2017-03-034-1/+271
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs 'statx()' update from Al Viro. This adds the new extended stat() interface that internally subsumes our previous stat interfaces, and allows user mode to specify in more detail what kind of information it wants. It also allows for some explicit synchronization information to be passed to the filesystem, which can be relevant for network filesystems: is the cached value ok, or do you need open/close consistency, or what? From David Howells. Andreas Dilger points out that the first version of the extended statx interface was posted June 29, 2010: https://www.spinics.net/lists/linux-fsdevel/msg33831.html * 'rebased-statx' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: statx: Add a system call to make enhanced file info available
| * statx: Add a system call to make enhanced file info availableDavid Howells2017-03-034-1/+271
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a system call to make extended file information available, including file creation and some attribute flags where available through the underlying filesystem. The getattr inode operation is altered to take two additional arguments: a u32 request_mask and an unsigned int flags that indicate the synchronisation mode. This change is propagated to the vfs_getattr*() function. Functions like vfs_stat() are now inline wrappers around new functions vfs_statx() and vfs_statx_fd() to reduce stack usage. ======== OVERVIEW ======== The idea was initially proposed as a set of xattrs that could be retrieved with getxattr(), but the general preference proved to be for a new syscall with an extended stat structure. A number of requests were gathered for features to be included. The following have been included: (1) Make the fields a consistent size on all arches and make them large. (2) Spare space, request flags and information flags are provided for future expansion. (3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an __s64). (4) Creation time: The SMB protocol carries the creation time, which could be exported by Samba, which will in turn help CIFS make use of FS-Cache as that can be used for coherency data (stx_btime). This is also specified in NFSv4 as a recommended attribute and could be exported by NFSD [Steve French]. (5) Lightweight stat: Ask for just those details of interest, and allow a netfs (such as NFS) to approximate anything not of interest, possibly without going to the server [Trond Myklebust, Ulrich Drepper, Andreas Dilger] (AT_STATX_DONT_SYNC). (6) Heavyweight stat: Force a netfs to go to the server, even if it thinks its cached attributes are up to date [Trond Myklebust] (AT_STATX_FORCE_SYNC). And the following have been left out for future extension: (7) Data version number: Could be used by userspace NFS servers [Aneesh Kumar]. Can also be used to modify fill_post_wcc() in NFSD which retrieves i_version directly, but has just called vfs_getattr(). It could get it from the kstat struct if it used vfs_xgetattr() instead. (There's disagreement on the exact semantics of a single field, since not all filesystems do this the same way). (8) BSD stat compatibility: Including more fields from the BSD stat such as creation time (st_btime) and inode generation number (st_gen) [Jeremy Allison, Bernd Schubert]. (9) Inode generation number: Useful for FUSE and userspace NFS servers [Bernd Schubert]. (This was asked for but later deemed unnecessary with the open-by-handle capability available and caused disagreement as to whether it's a security hole or not). (10) Extra coherency data may be useful in making backups [Andreas Dilger]. (No particular data were offered, but things like last backup timestamp, the data version number and the DOS archive bit would come into this category). (11) Allow the filesystem to indicate what it can/cannot provide: A filesystem can now say it doesn't support a standard stat feature if that isn't available, so if, for instance, inode numbers or UIDs don't exist or are fabricated locally... (This requires a separate system call - I have an fsinfo() call idea for this). (12) Store a 16-byte volume ID in the superblock that can be returned in struct xstat [Steve French]. (Deferred to fsinfo). (13) Include granularity fields in the time data to indicate the granularity of each of the times (NFSv4 time_delta) [Steve French]. (Deferred to fsinfo). (14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags. Note that the Linux IOC flags are a mess and filesystems such as Ext4 define flags that aren't in linux/fs.h, so translation in the kernel may be a necessity (or, possibly, we provide the filesystem type too). (Some attributes are made available in stx_attributes, but the general feeling was that the IOC flags were to ext[234]-specific and shouldn't be exposed through statx this way). (15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer, Michael Kerrisk]. (Deferred, probably to fsinfo. Finding out if there's an ACL or seclabal might require extra filesystem operations). (16) Femtosecond-resolution timestamps [Dave Chinner]. (A __reserved field has been left in the statx_timestamp struct for this - if there proves to be a need). (17) A set multiple attributes syscall to go with this. =============== NEW SYSTEM CALL =============== The new system call is: int ret = statx(int dfd, const char *filename, unsigned int flags, unsigned int mask, struct statx *buffer); The dfd, filename and flags parameters indicate the file to query, in a similar way to fstatat(). There is no equivalent of lstat() as that can be emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is also no equivalent of fstat() as that can be emulated by passing a NULL filename to statx() with the fd of interest in dfd. Whether or not statx() synchronises the attributes with the backing store can be controlled by OR'ing a value into the flags argument (this typically only affects network filesystems): (1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this respect. (2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise its attributes with the server - which might require data writeback to occur to get the timestamps correct. (3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a network filesystem. The resulting values should be considered approximate. mask is a bitmask indicating the fields in struct statx that are of interest to the caller. The user should set this to STATX_BASIC_STATS to get the basic set returned by stat(). It should be noted that asking for more information may entail extra I/O operations. buffer points to the destination for the data. This must be 256 bytes in size. ====================== MAIN ATTRIBUTES RECORD ====================== The following structures are defined in which to return the main attribute set: struct statx_timestamp { __s64 tv_sec; __s32 tv_nsec; __s32 __reserved; }; struct statx { __u32 stx_mask; __u32 stx_blksize; __u64 stx_attributes; __u32 stx_nlink; __u32 stx_uid; __u32 stx_gid; __u16 stx_mode; __u16 __spare0[1]; __u64 stx_ino; __u64 stx_size; __u64 stx_blocks; __u64 __spare1[1]; struct statx_timestamp stx_atime; struct statx_timestamp stx_btime; struct statx_timestamp stx_ctime; struct statx_timestamp stx_mtime; __u32 stx_rdev_major; __u32 stx_rdev_minor; __u32 stx_dev_major; __u32 stx_dev_minor; __u64 __spare2[14]; }; The defined bits in request_mask and stx_mask are: STATX_TYPE Want/got stx_mode & S_IFMT STATX_MODE Want/got stx_mode & ~S_IFMT STATX_NLINK Want/got stx_nlink STATX_UID Want/got stx_uid STATX_GID Want/got stx_gid STATX_ATIME Want/got stx_atime{,_ns} STATX_MTIME Want/got stx_mtime{,_ns} STATX_CTIME Want/got stx_ctime{,_ns} STATX_INO Want/got stx_ino STATX_SIZE Want/got stx_size STATX_BLOCKS Want/got stx_blocks STATX_BASIC_STATS [The stuff in the normal stat struct] STATX_BTIME Want/got stx_btime{,_ns} STATX_ALL [All currently available stuff] stx_btime is the file creation time, stx_mask is a bitmask indicating the data provided and __spares*[] are where as-yet undefined fields can be placed. Time fields are structures with separate seconds and nanoseconds fields plus a reserved field in case we want to add even finer resolution. Note that times will be negative if before 1970; in such a case, the nanosecond fields will also be negative if not zero. The bits defined in the stx_attributes field convey information about a file, how it is accessed, where it is and what it does. The following attributes map to FS_*_FL flags and are the same numerical value: STATX_ATTR_COMPRESSED File is compressed by the fs STATX_ATTR_IMMUTABLE File is marked immutable STATX_ATTR_APPEND File is append-only STATX_ATTR_NODUMP File is not to be dumped STATX_ATTR_ENCRYPTED File requires key to decrypt in fs Within the kernel, the supported flags are listed by: KSTAT_ATTR_FS_IOC_FLAGS [Are any other IOC flags of sufficient general interest to be exposed through this interface?] New flags include: STATX_ATTR_AUTOMOUNT Object is an automount trigger These are for the use of GUI tools that might want to mark files specially, depending on what they are. Fields in struct statx come in a number of classes: (0) stx_dev_*, stx_blksize. These are local system information and are always available. (1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino, stx_size, stx_blocks. These will be returned whether the caller asks for them or not. The corresponding bits in stx_mask will be set to indicate whether they actually have valid values. If the caller didn't ask for them, then they may be approximated. For example, NFS won't waste any time updating them from the server, unless as a byproduct of updating something requested. If the values don't actually exist for the underlying object (such as UID or GID on a DOS file), then the bit won't be set in the stx_mask, even if the caller asked for the value. In such a case, the returned value will be a fabrication. Note that there are instances where the type might not be valid, for instance Windows reparse points. (2) stx_rdev_*. This will be set only if stx_mode indicates we're looking at a blockdev or a chardev, otherwise will be 0. (3) stx_btime. Similar to (1), except this will be set to 0 if it doesn't exist. ======= TESTING ======= The following test program can be used to test the statx system call: samples/statx/test-statx.c Just compile and run, passing it paths to the files you want to examine. The file is built automatically if CONFIG_SAMPLES is enabled. Here's some example output. Firstly, an NFS directory that crosses to another FSID. Note that the AUTOMOUNT attribute is set because transiting this directory will cause d_automount to be invoked by the VFS. [root@andromeda ~]# /tmp/test-statx -A /warthog/data statx(/warthog/data) = 0 results=7ff Size: 4096 Blocks: 8 IO Block: 1048576 directory Device: 00:26 Inode: 1703937 Links: 125 Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041 Access: 2016-11-24 09:02:12.219699527+0000 Modify: 2016-11-17 10:44:36.225653653+0000 Change: 2016-11-17 10:44:36.225653653+0000 Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------) Secondly, the result of automounting on that directory. [root@andromeda ~]# /tmp/test-statx /warthog/data statx(/warthog/data) = 0 results=7ff Size: 4096 Blocks: 8 IO Block: 1048576 directory Device: 00:27 Inode: 2 Links: 125 Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041 Access: 2016-11-24 09:02:12.219699527+0000 Modify: 2016-11-17 10:44:36.225653653+0000 Change: 2016-11-17 10:44:36.225653653+0000 Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-19 13:44:30 +0100