* Re: [PATCH v5 3/4] LSM: Define SELinux function to measure state and policy
From: Lakshmi Ramasubramanian @ 2020-08-03 16:14 UTC (permalink / raw)
To: Stephen Smalley, zohar, casey
Cc: tyhicks, sashal, jmorris, linux-integrity, selinux,
linux-security-module, linux-kernel
In-Reply-To: <dfd6f9c8-d62a-d278-9b0e-6b1f5ad03d3e@gmail.com>
On 8/3/20 8:11 AM, Stephen Smalley wrote:
>
> Possibly I'm missing something but with these patches applied on top of
> next-integrity, and the following lines added to /etc/ima/ima-policy:
>
> measure func=LSM_STATE template=ima-buf
> measure func=LSM_POLICY
>
> I still don't get the selinux-state or selinux-policy-hash entries in
> the ascii_runtime_measurements file. No errors during loading of the
> ima policy as far as I can see.
>
Could you please check if the following config is set?
CONFIG_IMA_QUEUE_EARLY_BOOT_DATA=y
Try changing /sys/fs/selinux/checkreqprot and check
ascii_runtime_measurements file again?
Also, could you please check if
/sys/kernel/security/integrity/ima/policy contains LSM_STATE and
LSM_POLICY entries?
-lakshmi
^ permalink raw reply
* Re: [PATCH v1 0/4] [RFC] Implement Trampoline File Descriptor
From: Madhavan T. Venkataraman @ 2020-08-03 16:03 UTC (permalink / raw)
To: David Laight, 'Mark Rutland'
Cc: Andy Lutomirski, Kernel Hardening, Linux API, linux-arm-kernel,
Linux FS Devel, linux-integrity, LKML, LSM List, Oleg Nesterov,
X86 ML
In-Reply-To: <a3068e3126a942c7a3e7ac115499deb1@AcuMS.aculab.com>
On 8/3/20 3:27 AM, David Laight wrote:
> From: Mark Rutland
>> Sent: 31 July 2020 19:32
> ...
>>> It requires PC-relative data references. I have not worked on all architectures.
>>> So, I need to study this. But do all ISAs support PC-relative data references?
>> Not all do, but pretty much any recent ISA will as it's a practical
>> necessity for fast position-independent code.
> i386 has neither PC-relative addressing nor moves from %pc.
> The cpu architecture knows that the sequence:
> call 1f
> 1: pop %reg
> is used to get the %pc value so is treated specially so that
> it doesn't 'trash' the return stack.
>
> So PIC code isn't too bad, but you have to use the correct
> sequence.
Is that true only for 32-bit systems only? I thought RIP-relative addressing was
introduced in 64-bit mode. Please confirm.
Madhavan
^ permalink raw reply
* Re: [PATCH v1 0/4] [RFC] Implement Trampoline File Descriptor
From: Madhavan T. Venkataraman @ 2020-08-03 15:59 UTC (permalink / raw)
To: David Laight, Andy Lutomirski
Cc: Kernel Hardening, Linux API, linux-arm-kernel, Linux FS Devel,
linux-integrity, LKML, LSM List, Oleg Nesterov, X86 ML
In-Reply-To: <a5fb2778a86f45b58ef5dd35228d950b@AcuMS.aculab.com>
On 8/3/20 3:23 AM, David Laight wrote:
> From: Madhavan T. Venkataraman
>> Sent: 02 August 2020 19:55
>> To: Andy Lutomirski <luto@kernel.org>
>> Cc: Kernel Hardening <kernel-hardening@lists.openwall.com>; Linux API <linux-api@vger.kernel.org>;
>> linux-arm-kernel <linux-arm-kernel@lists.infradead.org>; Linux FS Devel <linux-
>> fsdevel@vger.kernel.org>; linux-integrity <linux-integrity@vger.kernel.org>; LKML <linux-
>> kernel@vger.kernel.org>; LSM List <linux-security-module@vger.kernel.org>; Oleg Nesterov
>> <oleg@redhat.com>; X86 ML <x86@kernel.org>
>> Subject: Re: [PATCH v1 0/4] [RFC] Implement Trampoline File Descriptor
>>
>> More responses inline..
>>
>> On 7/28/20 12:31 PM, Andy Lutomirski wrote:
>>>> On Jul 28, 2020, at 6:11 AM, madvenka@linux.microsoft.com wrote:
>>>>
>>>> From: "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com>
>>>>
>>> 2. Use existing kernel functionality. Raise a signal, modify the
>>> state, and return from the signal. This is very flexible and may not
>>> be all that much slower than trampfd.
>> Let me understand this. You are saying that the trampoline code
>> would raise a signal and, in the signal handler, set up the context
>> so that when the signal handler returns, we end up in the target
>> function with the context correctly set up. And, this trampoline code
>> can be generated statically at build time so that there are no
>> security issues using it.
>>
>> Have I understood your suggestion correctly?
> I was thinking that you'd just let the 'not executable' page fault
> signal happen (SIGSEGV?) when the code jumps to on-stack trampoline
> is executed.
>
> The user signal handler can then decode the faulting instruction
> and, if it matches the expected on-stack trampoline, modify the
> saved registers before returning from the signal.
>
> No kernel changes and all you need to add to the program is
> an architecture-dependant signal handler.
Understood.
Madhavan
^ permalink raw reply
* Re: [PATCH v1 0/4] [RFC] Implement Trampoline File Descriptor
From: Madhavan T. Venkataraman @ 2020-08-03 15:57 UTC (permalink / raw)
To: David Laight, 'Pavel Machek'
Cc: 'Andy Lutomirski', Kernel Hardening, Linux API,
linux-arm-kernel, Linux FS Devel, linux-integrity, LKML, LSM List,
Oleg Nesterov, X86 ML
In-Reply-To: <c02fbae7a0754a58884b370657575845@AcuMS.aculab.com>
On 8/3/20 3:08 AM, David Laight wrote:
> From: Pavel Machek <pavel@ucw.cz>
>> Sent: 02 August 2020 12:56
>> Hi!
>>
>>>> This is quite clever, but now I???m wondering just how much kernel help
>>>> is really needed. In your series, the trampoline is an non-executable
>>>> page. I can think of at least two alternative approaches, and I'd
>>>> like to know the pros and cons.
>>>>
>>>> 1. Entirely userspace: a return trampoline would be something like:
>>>>
>>>> 1:
>>>> pushq %rax
>>>> pushq %rbc
>>>> pushq %rcx
>>>> ...
>>>> pushq %r15
>>>> movq %rsp, %rdi # pointer to saved regs
>>>> leaq 1b(%rip), %rsi # pointer to the trampoline itself
>>>> callq trampoline_handler # see below
>>> For nested calls (where the trampoline needs to pass the
>>> original stack frame to the nested function) I think you
>>> just need a page full of:
>>> mov $0, scratch_reg; jmp trampoline_handler
>> I believe you could do with mov %pc, scratch_reg; jmp ...
>>
>> That has advantage of being able to share single physical
>> page across multiple virtual pages...
> A lot of architecture don't let you copy %pc that way so you would
> have to use 'call' - but that trashes the return address cache.
> It also needs the trampoline handler to know the addresses
> of the trampolines.
Do you which ones don't allow you to copy %pc?
Some of the architctures do not have PC-relative data references.
If they do not allow you to copy the PC into a general purpose
register, then there is no way to implement the statically defined
trampoline that has been discussed so far. In these cases, the
trampoline has to be generate at runtime.
Thanks.
Madhavan
^ permalink raw reply
* [GIT PULL] Filesystem Information
From: David Howells @ 2020-08-03 15:49 UTC (permalink / raw)
To: Linus Torvalds
Cc: dhowells, viro, raven, kzak, jlayton, mszeredi, nicolas.dichtel,
christian, lennart, linux-api, linux-fsdevel,
linux-security-module, linux-kernel
In-Reply-To: <1842689.1596468469@warthog.procyon.org.uk>
Hi Linus,
Here's a set of patches that adds a system call, fsinfo(), that allows
information about the VFS, mount topology, superblock and files to be
retrieved.
The patchset is based on top of the mount notifications patchset so that
the mount notification mechanism can be hooked to provide event counters
that can be retrieved with fsinfo(), thereby making it a lot faster to work
out which mounts have changed.
Note that there was a last minute change requested by Miklós: the event
counter bits got moved from the mount notification patchset to this one.
The counters got made atomic_long_t inside the kernel and __u64 in the
UAPI. The aggregate changes can be assessed by comparing pre-change tag,
fsinfo-core-20200724 to the requested pull tag.
Karel Zak has created preliminary patches that add support to libmount[*]
and Ian Kent has started working on making systemd use these and mount
notifications[**].
[*] https://github.com/karelzak/util-linux/commits/topic/fsinfo
[**] https://lists.freedesktop.org/archives/systemd-devel/2020-July/044914.html
=======
THE WHY
=======
Why do we want this?
Using /proc/mounts (or similar) has problems:
(1) Reading from it holds a global lock (namespace_sem) that prevents
mounting and unmounting. Lots of data is encoded and mangled into
text whilst the lock is held, including superblock option strings and
mount point paths. This causes performance problems when there are a
lot of mount objects in a system.
(2) Even though namespace_sem is held during a read, reading the whole
file isn't necessarily atomic with respect to mount-type operations.
If a read isn't satisfied in one go, then it may return to userspace
briefly and then continue reading some way into the file. But changes
can occur in the interval that may then go unseen.
(3) Determining what has changed means parsing and comparing consecutive
outputs of /proc/mounts.
(4) Querying a specific mount or superblock means searching through
/proc/mounts and searching by path or mount ID - but we might have an
fd we want to query.
(5) Whilst you can poll() it for events, it only tells you that something
changed in the namespace, not what or whether you can even see the
change.
To fix the notification issues, the preceding notifications patchset added
mount watch notifications whereby you can watch for notifications in a
specific mount subtree. The notification messages include the ID(s) of the
affected mounts.
To support notifications, however, we need to be able to handle overruns in
the notification queue. I added a number of event counters to struct
super_block and struct mount to allow you to pin down the changes, but
there needs to be a way to retrieve them. Exposing them through /proc
would require adding yet another /proc/mounts-type file. We could add
per-mount directories full of attributes in sysfs, but that has issues also
(see below).
Adding an extensible system call interface for retrieving filesystem
information also allows other things to be exposed:
(1) Jeff Layton's error handling changes need a way to allow error event
information to be retrieved.
(2) Bits in masks returned by things like statx() and FS_IOC_GETFLAGS are
actually 3-state { Set, Unset, Not supported }. It could be useful to
provide a way to expose information like this[*].
(3) Limits of the numerical metadata values in a filesystem[*].
(4) Filesystem capability information[*]. Filesystems don't all have the
same capabilities, and even different instances may have different
capabilities, particularly with network filesystems where the set of
may be server-dependent. Capabilities might even vary at file
granularity - though possibly such information should be conveyed
through statx() instead.
(5) ID mapping/shifting tables in use for a superblock.
(6) Filesystem-specific information. I need something for AFS so that I
can do pioctl()-emulation, thereby allowing me to implement certain of
the AFS command line utilities that query state of a particular file.
This could also have application for other filesystems, such as NFS,
CIFS and ext4.
[*] In a lot of cases these are probably invariant and can be memcpy'd
from static data.
There's a further consideration: I want to make it possible to have
fsconfig(fd, FSCONFIG_CMD_CREATE) be intercepted by a container manager
such that the manager can supervise a mount attempted inside the container.
The manager would be given an fd pointing to the fs_context struct and
would then need some way to query it (fsinfo()) and modify it (fsconfig()).
This could also be used to arbitrate user-requested mounts when containers
are not in play.
================
DESIGN DECISIONS
================
(1) Information is partitioned into sets of attributes.
(2) Attribute IDs are integers as they're fast to compare.
(3) Attribute values are typed (struct, list of structs, string, opaque
blob). They type is fixed for a particular attribute.
(4) For structure types, the length is also a version. New fields can be
tacked onto the end.
(5) When copying a versioned struct to userspace, the core handles a
version mismatch by truncating or zero-padding the data as necessary.
This is transparent to the filesystem.
(6) The core handles all the buffering and buffer resizing.
(7) The filesystem never gets any access to the userspace parameter buffer
or result buffer.
(8) "Meta" attributes can describe other attributes.
========
OVERVIEW
========
fsinfo() is a system call that allows information about the filesystem at a
particular path point to be queried as a set of attributes.
Attribute values are of four basic types:
(1) Structure with version-dependent length (the length is the version).
(2) Variable-length string.
(3) List of structures (all the same length).
(4) Opaque blob.
Attributes can have multiple values either as a sequence of values or a
sequence-of-sequences of values and all the values of a particular
attribute must be of the same type. Values can be up to INT_MAX size,
subject to memory availability.
Note that the values of an attribute *are* allowed to vary between dentries
within a single superblock, depending on the specific dentry that you're
looking at, but the values still have to be of the type for that attribute.
I've tried to make the interface as light as possible, so integer attribute
IDs rather than string and the core does all the buffer allocation and
expansion and all the extensibility support work rather than leaving that
to the filesystems. This also means that userspace pointers are not
exposed to the filesystem.
fsinfo() allows a variety of information to be retrieved about a filesystem
and the mount topology:
(1) General superblock attributes:
- Filesystem identifiers (UUID, volume label, device numbers, ...)
- The limits on a filesystem's capabilities
- Information on supported statx fields and attributes and IOC flags.
- A variety single-bit flags indicating supported capabilities.
- Timestamp resolution and range.
- The amount of space/free space in a filesystem (as statfs()).
- Superblock notification counter.
(2) Filesystem-specific superblock attributes:
- Superblock-level timestamps.
- Cell name, workgroup or other netfs grouping concept.
- Server names and addresses.
(3) VFS information:
- Mount topology information.
- Mount attributes.
- Mount notification counter.
- Mount point path.
(4) Information about what the fsinfo() syscall itself supports, including
the type and struct size of attributes.
The system is extensible:
(1) New attributes can be added. There is no requirement that a
filesystem implement every attribute. A helper function is provided
to scan a list of attributes and a filesystem can have multiple such
lists.
(2) Version length-dependent structure attributes can be made larger and
have additional information tacked on the end, provided it keeps the
layout of the existing fields. If an older process asks for a shorter
structure, it will only be given the bits it asks for. If a newer
process asks for a longer structure on an older kernel, the extra
space will be set to 0. In all cases, the size of the data actually
available is returned.
In essence, the size of a structure is that structure's version: a
smaller size is an earlier version and a later version includes
everything that the earlier version did.
(3) New single-bit capability flags can be added. This is a structure-typed
attribute and, as such, (2) applies. Any bits you wanted but the kernel
doesn't support are automatically set to 0.
fsinfo() may be called like the following, for example:
struct fsinfo_params params = {
.at_flags = AT_SYMLINK_NOFOLLOW,
.flags = FSINFO_FLAGS_QUERY_PATH,
.request = FSINFO_ATTR_AFS_SERVER_ADDRESSES,
.Nth = 2,
};
struct fsinfo_server_address address;
len = fsinfo(AT_FDCWD, "/afs/grand.central.org/doc",
¶ms, sizeof(params),
&address, sizeof(address));
The above example would query an AFS filesystem to retrieve the address
list for the 3rd server, and:
struct fsinfo_params params = {
.at_flags = AT_SYMLINK_NOFOLLOW,
.flags = FSINFO_FLAGS_QUERY_PATH,
.request = FSINFO_ATTR_NFS_SERVER_NAME;
};
char server_name[256];
len = fsinfo(AT_FDCWD, "/home/dhowells/",
¶ms, sizeof(params),
&server_name, sizeof(server_name));
would retrieve the name of the NFS server as a string.
In future, I want to make fsinfo() capable of querying a context created by
fsopen() or fspick(), e.g.:
fd = fsopen("ext4", 0);
struct fsinfo_params params = {
.flags = FSINFO_FLAGS_QUERY_FSCONTEXT,
.request = FSINFO_ATTR_CONFIGURATION;
};
char buffer[65536];
fsinfo(fd, NULL, ¶ms, sizeof(params), &buffer, sizeof(buffer));
even if that context doesn't currently have a superblock attached.
David
---
The following changes since commit 841a0dfa511364fa9a8d67512e0643669f1f03e3:
watch_queue: sample: Display mount tree change notifications (2020-08-03 12:15:38 +0100)
are available in the Git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git tags/fsinfo-core-20200803
for you to fetch changes up to 19d687f5902b65a158c5bec904d65d0525ea4efe:
samples: add error state information to test-fsinfo.c (2020-08-03 13:43:46 +0100)
----------------------------------------------------------------
Filesystem information
----------------------------------------------------------------
David Howells (15):
fsinfo: Introduce a non-repeating system-unique superblock ID
fsinfo: Add fsinfo() syscall to query filesystem information
fsinfo: Provide a bitmap of the features a filesystem supports
fsinfo: Allow retrieval of superblock devname, options and stats
fsinfo: Allow fsinfo() to look up a mount object by ID
fsinfo: Add a uniquifier ID to struct mount
fsinfo: Allow mount information to be queried
fsinfo: Allow mount topology and propagation info to be retrieved
watch_queue: Mount event counters
fsinfo: Provide notification overrun handling support
fsinfo: sample: Mount listing program
fsinfo: Add API documentation
fsinfo: Add support for AFS
fsinfo: Add support to ext4
fsinfo: Add an attribute that lists all the visible mounts in a namespace
Jeff Layton (3):
errseq: add a new errseq_scrape function
vfs: allow fsinfo to fetch the current state of s_wb_err
samples: add error state information to test-fsinfo.c
Documentation/filesystems/fsinfo.rst | 574 ++++++++++++++++++
arch/alpha/kernel/syscalls/syscall.tbl | 1 +
arch/arm/tools/syscall.tbl | 1 +
arch/arm64/include/asm/unistd.h | 2 +-
arch/arm64/include/asm/unistd32.h | 2 +
arch/ia64/kernel/syscalls/syscall.tbl | 1 +
arch/m68k/kernel/syscalls/syscall.tbl | 1 +
arch/microblaze/kernel/syscalls/syscall.tbl | 1 +
arch/mips/kernel/syscalls/syscall_n32.tbl | 1 +
arch/mips/kernel/syscalls/syscall_n64.tbl | 1 +
arch/mips/kernel/syscalls/syscall_o32.tbl | 1 +
arch/parisc/kernel/syscalls/syscall.tbl | 1 +
arch/powerpc/kernel/syscalls/syscall.tbl | 1 +
arch/s390/kernel/syscalls/syscall.tbl | 1 +
arch/sh/kernel/syscalls/syscall.tbl | 1 +
arch/sparc/kernel/syscalls/syscall.tbl | 1 +
arch/x86/entry/syscalls/syscall_32.tbl | 1 +
arch/x86/entry/syscalls/syscall_64.tbl | 1 +
arch/xtensa/kernel/syscalls/syscall.tbl | 1 +
fs/Kconfig | 7 +
fs/Makefile | 1 +
fs/afs/internal.h | 1 +
fs/afs/super.c | 216 ++++++-
fs/d_path.c | 2 +-
fs/ext4/Makefile | 1 +
fs/ext4/ext4.h | 6 +
fs/ext4/fsinfo.c | 97 +++
fs/ext4/super.c | 3 +
fs/fsinfo.c | 748 +++++++++++++++++++++++
fs/internal.h | 16 +
fs/mount.h | 6 +
fs/mount_notify.c | 10 +-
fs/namespace.c | 427 +++++++++++++-
fs/super.c | 2 +
include/linux/errseq.h | 1 +
include/linux/fs.h | 7 +
include/linux/fsinfo.h | 112 ++++
include/linux/syscalls.h | 4 +
include/uapi/asm-generic/unistd.h | 4 +-
include/uapi/linux/fsinfo.h | 344 +++++++++++
include/uapi/linux/mount.h | 13 +-
kernel/sys_ni.c | 1 +
lib/errseq.c | 33 +-
samples/vfs/Makefile | 6 +-
samples/vfs/test-fsinfo.c | 883 ++++++++++++++++++++++++++++
samples/vfs/test-mntinfo.c | 277 +++++++++
46 files changed, 3808 insertions(+), 14 deletions(-)
create mode 100644 Documentation/filesystems/fsinfo.rst
create mode 100644 fs/ext4/fsinfo.c
create mode 100644 fs/fsinfo.c
create mode 100644 include/linux/fsinfo.h
create mode 100644 include/uapi/linux/fsinfo.h
create mode 100644 samples/vfs/test-fsinfo.c
create mode 100644 samples/vfs/test-mntinfo.c
^ permalink raw reply
* Re: [PATCH bpf-next v7 5/7] bpf: Implement bpf_local_storage for inodes
From: KP Singh @ 2020-08-03 15:41 UTC (permalink / raw)
To: Martin KaFai Lau
Cc: linux-kernel, bpf, linux-security-module, Alexei Starovoitov,
Daniel Borkmann, Paul Turner, Jann Horn, Florent Revest
In-Reply-To: <20200731190226.6ugmk6cnl2yortgt@kafai-mbp.dhcp.thefacebook.com>
On 31.07.20 21:02, Martin KaFai Lau wrote:
> On Fri, Jul 31, 2020 at 02:08:55PM +0200, KP Singh wrote:
> [ ... ]
>>>> +const struct bpf_map_ops inode_storage_map_ops = {
[...]
>>
>> btf dump file /sys/kernel/btf/vmlinux | grep "STRUCT 'inode'"
>> "[915] STRUCT 'inode' size=984 vlen=48
>>
>> So it seems like btf_id[0] and btf_id[1] are set to the BTF ID
>> for inode. Now I think this might just be a coincidence as
>> the next helper (bpf_inode_storage_delete)
>> also has a BTF argument of type inode.
> It seems the next BTF_ID_LIST(bpf_inode_storage_delete_btf_ids)
> is not needed because they are the same. I think one
> BTF_ID_LIST(bpf_inode_btf_ids) can be used for both helpers.
>
Cool, yeah. I have fixed it and also for sock helpers. Will
send a new series out.
- KP
>>
>> and sure enough if I call:
>>
>> bpf_inode_storage_delete from my selftests program,
>> it does not load:
[...]
>> ./test_progs -t test_local_storage
>> [ 20.577223] btf_ids[0]=0
>> [ 20.577702] btf_ids[1]=915
>>
>> Thanks for noticing this!
>>
>> - KP
>>
>>>
>>>> +
>>>> +const struct bpf_func_proto bpf_inode_storage_get_proto = {
>>>> + .func = bpf_inode_storage_get,
>>>> + .gpl_only = false,
>>>> + .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
>>>> + .arg1_type = ARG_CONST_MAP_PTR,
>>>> + .arg2_type = ARG_PTR_TO_BTF_ID,
>>>> + .arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL,
>>>> + .arg4_type = ARG_ANYTHING,
>>>> + .btf_id = bpf_inode_storage_get_btf_ids,
>>>> +};
>>>> +
>>>> +BTF_ID_LIST(bpf_inode_storage_delete_btf_ids)
>>>> +BTF_ID(struct, inode)
>>>> +
>>>> +const struct bpf_func_proto bpf_inode_storage_delete_proto = {
>>>> + .func = bpf_inode_storage_delete,
>>>> + .gpl_only = false,
>>>> + .ret_type = RET_INTEGER,
>>>> + .arg1_type = ARG_CONST_MAP_PTR,
>>>> + .arg2_type = ARG_PTR_TO_BTF_ID,
>>>> + .btf_id = bpf_inode_storage_delete_btf_ids,
>>>> +};
^ permalink raw reply
* [GIT PULL] Mount notifications
From: David Howells @ 2020-08-03 15:27 UTC (permalink / raw)
To: Linus Torvalds
Cc: dhowells, viro, raven, kzak, jlayton, mszeredi, nicolas.dichtel,
christian, linux-api, linux-fsdevel, linux-security-module,
linux-kernel
Hi Linus,
Here's a set of patches to add notifications for mount topology events,
such as mounting, unmounting, mount expiry, mount reconfiguration.
The first patch in the series adds a hard limit on the number of watches
that any particular user can add. The RLIMIT_NOFILE value for the process
adding a watch is used as the limit. Even if you don't take the rest of
the series, can you at least take this one?
An LSM hook is included for an LSM to rule on whether or not a mount watch
may be set on a particular path.
This series is intended to be taken in conjunction with the fsinfo series
which I'll post a pull request for shortly and which is dependent on it.
Karel Zak[*] has created preliminary patches that add support to libmount
and Ian Kent has started working on making systemd use them.
[*] https://github.com/karelzak/util-linux/commits/topic/fsinfo
Note that there have been some last minute changes to the patchset: you
wanted something adding and Miklós wanted some bits taking out/changing.
I've placed a tag, fsinfo-core-20200724 on the aggregate of these two
patchsets that can be compared to fsinfo-core-20200803.
To summarise the changes: I added the limiter that you wanted; removed an
unused symbol; made the mount ID fields in the notificaion 64-bit (the
fsinfo patchset has a change to convey the mount uniquifier instead of the
mount ID); removed the event counters from the mount notification and moved
the event counters into the fsinfo patchset.
====
WHY?
====
Why do we want mount notifications? Whilst /proc/mounts can be polled, it
only tells you that something changed in your namespace. To find out, you
have to trawl /proc/mounts or similar to work out what changed in the mount
object attributes and mount topology. I'm told that the proc file holding
the namespace_sem is a point of contention, especially as the process of
generating the text descriptions of the mounts/superblocks can be quite
involved.
The notification generated here directly indicates the mounts involved in
any particular event and gives an idea of what the change was.
This is combined with a new fsinfo() system call that allows, amongst other
things, the ability to retrieve in one go an { id, change_counter } tuple
from all the children of a specified mount, allowing buffer overruns to be
dealt with quickly.
This is of use to systemd to improve efficiency:
https://lore.kernel.org/linux-fsdevel/20200227151421.3u74ijhqt6ekbiss@ws.net.home/
And it's not just Red Hat that's potentially interested in this:
https://lore.kernel.org/linux-fsdevel/293c9bd3-f530-d75e-c353-ddeabac27cf6@6wind.com/
David
---
The following changes since commit ba47d845d715a010f7b51f6f89bae32845e6acb7:
Linux 5.8-rc6 (2020-07-19 15:41:18 -0700)
are available in the Git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git tags/mount-notifications-20200803
for you to fetch changes up to 841a0dfa511364fa9a8d67512e0643669f1f03e3:
watch_queue: sample: Display mount tree change notifications (2020-08-03 12:15:38 +0100)
----------------------------------------------------------------
Mount notifications
----------------------------------------------------------------
David Howells (5):
watch_queue: Limit the number of watches a user can hold
watch_queue: Make watch_sizeof() check record size
watch_queue: Add security hooks to rule on setting mount watches
watch_queue: Implement mount topology and attribute change notifications
watch_queue: sample: Display mount tree change notifications
Documentation/watch_queue.rst | 12 +-
arch/alpha/kernel/syscalls/syscall.tbl | 1 +
arch/arm/tools/syscall.tbl | 1 +
arch/arm64/include/asm/unistd.h | 2 +-
arch/arm64/include/asm/unistd32.h | 2 +
arch/ia64/kernel/syscalls/syscall.tbl | 1 +
arch/m68k/kernel/syscalls/syscall.tbl | 1 +
arch/microblaze/kernel/syscalls/syscall.tbl | 1 +
arch/mips/kernel/syscalls/syscall_n32.tbl | 1 +
arch/mips/kernel/syscalls/syscall_n64.tbl | 1 +
arch/mips/kernel/syscalls/syscall_o32.tbl | 1 +
arch/parisc/kernel/syscalls/syscall.tbl | 1 +
arch/powerpc/kernel/syscalls/syscall.tbl | 1 +
arch/s390/kernel/syscalls/syscall.tbl | 1 +
arch/sh/kernel/syscalls/syscall.tbl | 1 +
arch/sparc/kernel/syscalls/syscall.tbl | 1 +
arch/x86/entry/syscalls/syscall_32.tbl | 1 +
arch/x86/entry/syscalls/syscall_64.tbl | 1 +
arch/xtensa/kernel/syscalls/syscall.tbl | 1 +
fs/Kconfig | 9 ++
fs/Makefile | 1 +
fs/mount.h | 18 +++
fs/mount_notify.c | 222 ++++++++++++++++++++++++++++
fs/namespace.c | 22 +++
include/linux/dcache.h | 1 +
include/linux/lsm_hook_defs.h | 3 +
include/linux/lsm_hooks.h | 6 +
include/linux/sched/user.h | 3 +
include/linux/security.h | 8 +
include/linux/syscalls.h | 2 +
include/linux/watch_queue.h | 7 +-
include/uapi/asm-generic/unistd.h | 4 +-
include/uapi/linux/watch_queue.h | 31 +++-
kernel/sys_ni.c | 3 +
kernel/watch_queue.c | 8 +
samples/watch_queue/watch_test.c | 41 ++++-
security/security.c | 7 +
37 files changed, 422 insertions(+), 6 deletions(-)
create mode 100644 fs/mount_notify.c
^ permalink raw reply
* Re: [PATCH v5 3/4] LSM: Define SELinux function to measure state and policy
From: Stephen Smalley @ 2020-08-03 15:11 UTC (permalink / raw)
To: Lakshmi Ramasubramanian, zohar, casey
Cc: tyhicks, sashal, jmorris, linux-integrity, selinux,
linux-security-module, linux-kernel
In-Reply-To: <20200730034724.3298-4-nramas@linux.microsoft.com>
On 7/29/20 11:47 PM, Lakshmi Ramasubramanian wrote:
> SELinux configuration and policy are some of the critical data for this
> security module that needs to be measured. This measurement can be used
> by an attestation service, for instance, to verify if the configuration
> and policies have been setup correctly and that they haven't been tampered
> with at runtime.
>
> Measure SELinux configuration, policy capabilities settings, and the
> loaded policy by calling the IMA hooks ima_measure_lsm_state() and
> ima_measure_lsm_policy() respectively.
>
> Sample measurement of SELinux state and hash of the policy:
>
> 10 e32e...5ac3 ima-buf sha256:86e8...4594 selinux-state-1595389364:287899386 696e697469616c697a65643d313b656e61626c65643d313b656e666f7263696e673d303b636865636b72657170726f743d313b6e6574776f726b5f706565725f636f6e74726f6c733d313b6f70656e5f7065726d733d313b657874656e6465645f736f636b65745f636c6173733d313b616c776179735f636865636b5f6e6574776f726b3d303b6367726f75705f7365636c6162656c3d313b6e6e705f6e6f737569645f7472616e736974696f6e3d313b67656e66735f7365636c6162656c5f73796d6c696e6b733d303
> 10 f4a7...9408 ima-ng sha256:8d1d...1834 selinux-policy-hash-1595389353:863934271
>
> To verify the measurement check the following:
>
> Execute the following command to extract the measured data
> from the IMA log for SELinux configuration (selinux-state).
>
> grep -m 1 "selinux-state" /sys/kernel/security/integrity/ima/ascii_runtime_measurements | cut -d' ' -f 6 | xxd -r -p
>
> The output should be the list of key-value pairs. For example,
> initialized=1;enabled=1;enforcing=0;checkreqprot=1;network_peer_controls=1;open_perms=1;extended_socket_class=1;always_check_network=0;cgroup_seclabel=1;nnp_nosuid_transition=1;genfs_seclabel_symlinks=0;
>
> To verify the measured data with the current SELinux state:
>
> => enabled should be set to 1 if /sys/fs/selinux folder exists,
> 0 otherwise
>
> For other entries, compare the integer value in the files
> => /sys/fs/selinux/enforce
> => /sys/fs/selinux/checkreqprot
> And, each of the policy capabilities files under
> => /sys/fs/selinux/policy_capabilities
>
> For selinux-policy-hash, the hash of SELinux policy is included
> in the IMA log entry.
>
> To verify the measured data with the current SELinux policy run
> the following commands and verify the output hash values match.
>
> sha256sum /sys/fs/selinux/policy | cut -d' ' -f 1
>
> grep -m 1 "selinux-policy-hash" /sys/kernel/security/integrity/ima/ascii_runtime_measurements | cut -d' ' -f 4
>
> Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
> Suggested-by: Stephen Smalley <stephen.smalley.work@gmail.com>
> Reported-by: kernel test robot <lkp@intel.com> # error: implicit declaration of function 'vfree'
> Reported-by: kernel test robot <lkp@intel.com> # error: implicit declaration of function 'crypto_alloc_shash'
> Reported-by: kernel test robot <lkp@intel.com> # sparse: symbol 'security_read_selinux_policy' was not declared. Should it be static?
Possibly I'm missing something but with these patches applied on top of
next-integrity, and the following lines added to /etc/ima/ima-policy:
measure func=LSM_STATE template=ima-buf
measure func=LSM_POLICY
I still don't get the selinux-state or selinux-policy-hash entries in
the ascii_runtime_measurements file. No errors during loading of the
ima policy as far as I can see.
^ permalink raw reply
* Re: [PATCH 13/17] watch_queue: Implement mount topology and attribute change notifications [ver #5]
From: Ian Kent @ 2020-08-03 14:30 UTC (permalink / raw)
To: David Howells
Cc: Miklos Szeredi, Linus Torvalds, Al Viro, Casey Schaufler,
Stephen Smalley, Nicolas Dichtel, Christian Brauner, andres,
Jeff Layton, dray, Karel Zak, keyrings, Linux API, linux-fsdevel,
LSM, linux-kernel
In-Reply-To: <1692826.1596457912@warthog.procyon.org.uk>
On Mon, 2020-08-03 at 13:31 +0100, David Howells wrote:
> Ian Kent <raven@themaw.net> wrote:
>
> > > I'm changing it so that the fields are 64-bit, but initialised
> > > with the
> > > existing mount ID in the notifications set. The fsinfo set
> > > changes that
> > > to a unique ID. I'm tempted to make the unique IDs start at
> > > UINT_MAX+1 to
> > > disambiguate them.
> >
> > Mmm ... so what would I use as a mount id that's not used, like
> > NULL
> > for strings?
>
> Zero is skipped, so you could use that.
>
> > I'm using -1 now but changing this will mean I need something
> > different.
>
> It's 64-bits, so you're not likely to see it reach -1, even if it
> does start
> at UINT_MAX+1.
Ha, either or, I don't think it will be a problem, there's
bound to be a few changes so the components using this will
need to change a bit before it's finalized, shouldn't be a
big deal I think. At least not for me and shouldn't be much
for libmount either I think.
Ian
^ permalink raw reply
* [PATCH 17/18] vfs: allow fsinfo to fetch the current state of s_wb_err [ver #21]
From: David Howells @ 2020-08-03 13:38 UTC (permalink / raw)
To: viro
Cc: Jeff Layton, dhowells, torvalds, raven, mszeredi, christian,
jannh, darrick.wong, kzak, jlayton, linux-api, linux-fsdevel,
linux-security-module, linux-kernel
In-Reply-To: <159646178122.1784947.11705396571718464082.stgit@warthog.procyon.org.uk>
From: Jeff Layton <jlayton@kernel.org>
Add a new "error_state" struct to fsinfo, and teach the kernel to fill
that out from sb->s_wb_err. There are two fields:
wb_error_last: the most recently recorded errno for the filesystem
wb_error_cookie: this value will change vs. the previously fetched
value if a new error was recorded since it was last
checked. Callers should treat this as an opaque value
that can be compared to earlier fetched values.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/fsinfo.c | 11 +++++++++++
include/uapi/linux/fsinfo.h | 13 +++++++++++++
2 files changed, 24 insertions(+)
diff --git a/fs/fsinfo.c b/fs/fsinfo.c
index f230124ffdf5..ea9d9821d76b 100644
--- a/fs/fsinfo.c
+++ b/fs/fsinfo.c
@@ -274,6 +274,16 @@ static int fsinfo_generic_seq_read(struct path *path, struct fsinfo_context *ctx
return m.count + 1;
}
+static int fsinfo_generic_error_state(struct path *path,
+ struct fsinfo_context *ctx)
+{
+ struct fsinfo_error_state *es = ctx->buffer;
+
+ es->wb_error_cookie = errseq_scrape(&path->dentry->d_sb->s_wb_err);
+ es->wb_error_last = es->wb_error_cookie & MAX_ERRNO;
+ return sizeof(*es);
+}
+
static const struct fsinfo_attribute fsinfo_common_attributes[] = {
FSINFO_VSTRUCT (FSINFO_ATTR_STATFS, fsinfo_generic_statfs),
FSINFO_VSTRUCT (FSINFO_ATTR_IDS, fsinfo_generic_ids),
@@ -286,6 +296,7 @@ static const struct fsinfo_attribute fsinfo_common_attributes[] = {
FSINFO_STRING (FSINFO_ATTR_SOURCE, fsinfo_generic_mount_source),
FSINFO_STRING (FSINFO_ATTR_CONFIGURATION, fsinfo_generic_seq_read),
FSINFO_STRING (FSINFO_ATTR_FS_STATISTICS, fsinfo_generic_seq_read),
+ FSINFO_VSTRUCT (FSINFO_ATTR_ERROR_STATE, fsinfo_generic_error_state),
FSINFO_LIST (FSINFO_ATTR_FSINFO_ATTRIBUTES, (void *)123UL),
FSINFO_VSTRUCT_N(FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO, (void *)123UL),
diff --git a/include/uapi/linux/fsinfo.h b/include/uapi/linux/fsinfo.h
index e40192d98648..dcd764771a7d 100644
--- a/include/uapi/linux/fsinfo.h
+++ b/include/uapi/linux/fsinfo.h
@@ -27,6 +27,7 @@
#define FSINFO_ATTR_SOURCE 0x09 /* Superblock source/device name (string) */
#define FSINFO_ATTR_CONFIGURATION 0x0a /* Superblock configuration/options (string) */
#define FSINFO_ATTR_FS_STATISTICS 0x0b /* Superblock filesystem statistics (string) */
+#define FSINFO_ATTR_ERROR_STATE 0x0c /* Superblock writeback error state */
#define FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO 0x100 /* Information about attr N (for path) */
#define FSINFO_ATTR_FSINFO_ATTRIBUTES 0x101 /* List of supported attrs (for path) */
@@ -328,4 +329,16 @@ struct fsinfo_afs_server_address {
#define FSINFO_ATTR_AFS_SERVER_ADDRESSES__STRUCT struct fsinfo_afs_server_address
+/*
+ * Information struct for fsinfo(FSINFO_ATTR_ERROR_STATE).
+ *
+ * Retrieve the error state for a filesystem.
+ */
+struct fsinfo_error_state {
+ __u32 wb_error_cookie; /* writeback error cookie */
+ __u32 wb_error_last; /* latest writeback error */
+};
+
+#define FSINFO_ATTR_ERROR_STATE__STRUCT struct fsinfo_error_state
+
#endif /* _UAPI_LINUX_FSINFO_H */
^ permalink raw reply related
* [PATCH 18/18] samples: add error state information to test-fsinfo.c [ver #21]
From: David Howells @ 2020-08-03 13:39 UTC (permalink / raw)
To: viro
Cc: Jeff Layton, dhowells, torvalds, raven, mszeredi, christian,
jannh, darrick.wong, kzak, jlayton, linux-api, linux-fsdevel,
linux-security-module, linux-kernel
In-Reply-To: <159646178122.1784947.11705396571718464082.stgit@warthog.procyon.org.uk>
From: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: David Howells <dhowells@redhat.com>
---
samples/vfs/test-fsinfo.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/samples/vfs/test-fsinfo.c b/samples/vfs/test-fsinfo.c
index 596fa5e71762..c359c3f52871 100644
--- a/samples/vfs/test-fsinfo.c
+++ b/samples/vfs/test-fsinfo.c
@@ -430,6 +430,15 @@ static void dump_afs_fsinfo_server_address(void *reply, unsigned int size)
printf("family=%u\n", ss->ss_family);
}
+static void dump_fsinfo_generic_error_state(void *reply, unsigned int size)
+{
+ struct fsinfo_error_state *es = reply;
+
+ printf("\n");
+ printf("\tlatest error : %d (%s)\n", es->wb_error_last, strerror(es->wb_error_last));
+ printf("\tcookie : 0x%x\n", es->wb_error_cookie);
+}
+
static void dump_string(void *reply, unsigned int size)
{
char *s = reply, *p;
@@ -518,6 +527,7 @@ static const struct fsinfo_attribute fsinfo_attributes[] = {
FSINFO_STRING (FSINFO_ATTR_AFS_CELL_NAME, string),
FSINFO_STRING (FSINFO_ATTR_AFS_SERVER_NAME, string),
FSINFO_LIST_N (FSINFO_ATTR_AFS_SERVER_ADDRESSES, afs_fsinfo_server_address),
+ FSINFO_VSTRUCT (FSINFO_ATTR_ERROR_STATE, fsinfo_generic_error_state),
{}
};
^ permalink raw reply related
* [PATCH 16/18] errseq: add a new errseq_scrape function [ver #21]
From: David Howells @ 2020-08-03 13:38 UTC (permalink / raw)
To: viro
Cc: Jeff Layton, Carlos Maiolino, dhowells, torvalds, raven, mszeredi,
christian, jannh, darrick.wong, kzak, jlayton, linux-api,
linux-fsdevel, linux-security-module, linux-kernel
In-Reply-To: <159646178122.1784947.11705396571718464082.stgit@warthog.procyon.org.uk>
From: Jeff Layton <jlayton@kernel.org>
To grab the current value of an errseq_t, mark it as seen and then
return the value with the seen bit masked off.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: David Howells <dhowells@redhat.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
---
include/linux/errseq.h | 1 +
lib/errseq.c | 33 +++++++++++++++++++++++++++++++--
2 files changed, 32 insertions(+), 2 deletions(-)
diff --git a/include/linux/errseq.h b/include/linux/errseq.h
index fc2777770768..de165623fa86 100644
--- a/include/linux/errseq.h
+++ b/include/linux/errseq.h
@@ -9,6 +9,7 @@ typedef u32 errseq_t;
errseq_t errseq_set(errseq_t *eseq, int err);
errseq_t errseq_sample(errseq_t *eseq);
+errseq_t errseq_scrape(errseq_t *eseq);
int errseq_check(errseq_t *eseq, errseq_t since);
int errseq_check_and_advance(errseq_t *eseq, errseq_t *since);
#endif
diff --git a/lib/errseq.c b/lib/errseq.c
index 81f9e33aa7e7..8ded0920eed3 100644
--- a/lib/errseq.c
+++ b/lib/errseq.c
@@ -108,7 +108,7 @@ errseq_t errseq_set(errseq_t *eseq, int err)
EXPORT_SYMBOL(errseq_set);
/**
- * errseq_sample() - Grab current errseq_t value.
+ * errseq_sample() - Grab current errseq_t value (or 0 if it hasn't been seen)
* @eseq: Pointer to errseq_t to be sampled.
*
* This function allows callers to initialise their errseq_t variable.
@@ -117,7 +117,7 @@ EXPORT_SYMBOL(errseq_set);
* see it the next time it checks for an error.
*
* Context: Any context.
- * Return: The current errseq value.
+ * Return: The current errseq value or 0 if it wasn't previously seen
*/
errseq_t errseq_sample(errseq_t *eseq)
{
@@ -130,6 +130,35 @@ errseq_t errseq_sample(errseq_t *eseq)
}
EXPORT_SYMBOL(errseq_sample);
+/**
+ * errseq_scrape() - Grab current errseq_t value
+ * @eseq: Pointer to errseq_t to be sampled.
+ *
+ * This function allows callers to scrape the current value of an errseq_t.
+ * Unlike errseq_sample, this will always return the current value with
+ * the SEEN flag unset, even when the value has not yet been seen.
+ *
+ * Context: Any context.
+ * Return: The current errseq value with ERRSEQ_SEEN masked off
+ */
+errseq_t errseq_scrape(errseq_t *eseq)
+{
+ errseq_t old = READ_ONCE(*eseq);
+
+ /*
+ * For the common case of no errors ever having been set, we can skip
+ * marking the SEEN bit. Once an error has been set, the value will
+ * never go back to zero.
+ */
+ if (old != 0) {
+ errseq_t new = old | ERRSEQ_SEEN;
+ if (old != new)
+ cmpxchg(eseq, old, new);
+ }
+ return old & ~ERRSEQ_SEEN;
+}
+EXPORT_SYMBOL(errseq_scrape);
+
/**
* errseq_check() - Has an error occurred since a particular sample point?
* @eseq: Pointer to errseq_t value to be checked.
^ permalink raw reply related
* [PATCH 15/18] fsinfo: Add an attribute that lists all the visible mounts in a namespace [ver #21]
From: David Howells @ 2020-08-03 13:38 UTC (permalink / raw)
To: viro
Cc: dhowells, torvalds, raven, mszeredi, christian, jannh,
darrick.wong, kzak, jlayton, linux-api, linux-fsdevel,
linux-security-module, linux-kernel
In-Reply-To: <159646178122.1784947.11705396571718464082.stgit@warthog.procyon.org.uk>
Add a filesystem attribute that exports a list of all the visible mounts in
a namespace, given the caller's chroot setting. The returned list is an
array of:
struct fsinfo_mount_child {
__u64 mnt_unique_id;
__u32 mnt_id;
__u32 parent_id;
__u32 mnt_notify_sum;
__u32 sb_notify_sum;
};
where each element contains a once-in-a-system-lifetime unique ID, the
mount ID (which may get reused), the parent mount ID and sums of the
notification/change counters for the mount and its superblock.
This works with a read lock on the namespace_sem, but ideally would do it
under the RCU read lock only.
Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/fsinfo.c | 1 +
fs/internal.h | 1 +
fs/namespace.c | 37 +++++++++++++++++++++++++++++++++++++
include/uapi/linux/fsinfo.h | 4 ++++
samples/vfs/test-fsinfo.c | 22 ++++++++++++++++++++++
5 files changed, 65 insertions(+)
diff --git a/fs/fsinfo.c b/fs/fsinfo.c
index 0540cce89555..f230124ffdf5 100644
--- a/fs/fsinfo.c
+++ b/fs/fsinfo.c
@@ -296,6 +296,7 @@ static const struct fsinfo_attribute fsinfo_common_attributes[] = {
FSINFO_STRING (FSINFO_ATTR_MOUNT_POINT, fsinfo_generic_mount_point),
FSINFO_STRING (FSINFO_ATTR_MOUNT_POINT_FULL, fsinfo_generic_mount_point_full),
FSINFO_LIST (FSINFO_ATTR_MOUNT_CHILDREN, fsinfo_generic_mount_children),
+ FSINFO_LIST (FSINFO_ATTR_MOUNT_ALL, fsinfo_generic_mount_all),
{}
};
diff --git a/fs/internal.h b/fs/internal.h
index cb5edcc7125a..267b4aaf0271 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -102,6 +102,7 @@ extern int fsinfo_generic_mount_topology(struct path *, struct fsinfo_context *)
extern int fsinfo_generic_mount_point(struct path *, struct fsinfo_context *);
extern int fsinfo_generic_mount_point_full(struct path *, struct fsinfo_context *);
extern int fsinfo_generic_mount_children(struct path *, struct fsinfo_context *);
+extern int fsinfo_generic_mount_all(struct path *, struct fsinfo_context *);
/*
* fs_struct.c
diff --git a/fs/namespace.c b/fs/namespace.c
index 122c12f9512b..1f2e06507244 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -4494,4 +4494,41 @@ int fsinfo_generic_mount_children(struct path *path, struct fsinfo_context *ctx)
return ctx->usage;
}
+/*
+ * Return information about all the mounts in the namespace referenced by the
+ * path.
+ */
+int fsinfo_generic_mount_all(struct path *path, struct fsinfo_context *ctx)
+{
+ struct mnt_namespace *ns;
+ struct mount *m, *p;
+ struct path chroot;
+ bool allow;
+
+ m = real_mount(path->mnt);
+ ns = m->mnt_ns;
+
+ get_fs_root(current->fs, &chroot);
+ rcu_read_lock();
+ allow = are_paths_connected(&chroot, path) || capable(CAP_SYS_ADMIN);
+ rcu_read_unlock();
+ path_put(&chroot);
+ if (!allow)
+ return -EPERM;
+
+ down_read(&namespace_sem);
+
+ list_for_each_entry(p, &ns->list, mnt_list) {
+ struct path mnt_root;
+
+ mnt_root.mnt = &p->mnt;
+ mnt_root.dentry = p->mnt.mnt_root;
+ if (are_paths_connected(path, &mnt_root))
+ fsinfo_store_mount(ctx, p, p == m);
+ }
+
+ up_read(&namespace_sem);
+ return ctx->usage;
+}
+
#endif /* CONFIG_FSINFO */
diff --git a/include/uapi/linux/fsinfo.h b/include/uapi/linux/fsinfo.h
index 81329de6905e..e40192d98648 100644
--- a/include/uapi/linux/fsinfo.h
+++ b/include/uapi/linux/fsinfo.h
@@ -37,6 +37,7 @@
#define FSINFO_ATTR_MOUNT_POINT_FULL 0x203 /* Absolute path of mount (string) */
#define FSINFO_ATTR_MOUNT_TOPOLOGY 0x204 /* Mount object topology */
#define FSINFO_ATTR_MOUNT_CHILDREN 0x205 /* Children of this mount (list) */
+#define FSINFO_ATTR_MOUNT_ALL 0x206 /* List all mounts in a namespace (list) */
#define FSINFO_ATTR_AFS_CELL_NAME 0x300 /* AFS cell name (string) */
#define FSINFO_ATTR_AFS_SERVER_NAME 0x301 /* Name of the Nth server (string) */
@@ -128,6 +129,8 @@ struct fsinfo_mount_topology {
/*
* Information struct element for fsinfo(FSINFO_ATTR_MOUNT_CHILDREN).
* - An extra element is placed on the end representing the parent mount.
+ *
+ * Information struct element for fsinfo(FSINFO_ATTR_MOUNT_ALL).
*/
struct fsinfo_mount_child {
__u64 mnt_unique_id; /* Kernel-lifetime unique mount ID */
@@ -139,6 +142,7 @@ struct fsinfo_mount_child {
};
#define FSINFO_ATTR_MOUNT_CHILDREN__STRUCT struct fsinfo_mount_child
+#define FSINFO_ATTR_MOUNT_ALL__STRUCT struct fsinfo_mount_child
/*
* Information struct for fsinfo(FSINFO_ATTR_STATFS).
diff --git a/samples/vfs/test-fsinfo.c b/samples/vfs/test-fsinfo.c
index 374825ab85b0..596fa5e71762 100644
--- a/samples/vfs/test-fsinfo.c
+++ b/samples/vfs/test-fsinfo.c
@@ -365,6 +365,27 @@ static void dump_fsinfo_generic_mount_children(void *reply, unsigned int size)
(unsigned long long)r->mnt_notify_sum, mp);
}
+static void dump_fsinfo_generic_mount_all(void *reply, unsigned int size)
+{
+ struct fsinfo_mount_child *r = reply;
+ ssize_t mplen;
+ char path[32], *mp;
+
+ struct fsinfo_params params = {
+ .flags = FSINFO_FLAGS_QUERY_MOUNT,
+ .request = FSINFO_ATTR_MOUNT_POINT_FULL,
+ };
+
+ sprintf(path, "%u", r->mnt_id);
+ mplen = get_fsinfo(path, "FSINFO_ATTR_MOUNT_POINT_FULL", ¶ms, (void **)&mp);
+ if (mplen < 0)
+ mp = "-";
+
+ printf("%5x %5x %12llx %10llu %s\n",
+ r->mnt_id, r->parent_id, (unsigned long long)r->mnt_unique_id,
+ r->mnt_notify_sum, mp);
+}
+
static void dump_afs_fsinfo_server_address(void *reply, unsigned int size)
{
struct fsinfo_afs_server_address *f = reply;
@@ -492,6 +513,7 @@ static const struct fsinfo_attribute fsinfo_attributes[] = {
FSINFO_STRING_N (FSINFO_ATTR_MOUNT_POINT, string),
FSINFO_STRING_N (FSINFO_ATTR_MOUNT_POINT_FULL, string),
FSINFO_LIST (FSINFO_ATTR_MOUNT_CHILDREN, fsinfo_generic_mount_children),
+ FSINFO_LIST (FSINFO_ATTR_MOUNT_ALL, fsinfo_generic_mount_all),
FSINFO_STRING (FSINFO_ATTR_AFS_CELL_NAME, string),
FSINFO_STRING (FSINFO_ATTR_AFS_SERVER_NAME, string),
^ permalink raw reply related
* [PATCH 14/18] fsinfo: Add support to ext4 [ver #21]
From: David Howells @ 2020-08-03 13:38 UTC (permalink / raw)
To: viro
Cc: Darrick J. Wong, Theodore Ts'o, Andreas Dilger, Eric Biggers,
linux-ext4, dhowells, torvalds, raven, mszeredi, christian, jannh,
darrick.wong, kzak, jlayton, linux-api, linux-fsdevel,
linux-security-module, linux-kernel
In-Reply-To: <159646178122.1784947.11705396571718464082.stgit@warthog.procyon.org.uk>
Add support to ext4, including the following:
(1) FSINFO_ATTR_SUPPORTS: Information about supported STATX attributes and
support for ioctls like FS_IOC_[GS]ETFLAGS and FS_IOC_FS[GS]ETXATTR.
(2) FSINFO_ATTR_FEATURES: Information about features supported by an ext4
filesystem, such as whether version counting, birth time and name case
folding are in operation.
(3) FSINFO_ATTR_VOLUME_NAME: The volume name from the superblock.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
cc: "Theodore Ts'o" <tytso@mit.edu>
cc: Andreas Dilger <adilger.kernel@dilger.ca>
cc: Eric Biggers <ebiggers@kernel.org>
cc: linux-ext4@vger.kernel.org
---
fs/ext4/Makefile | 1 +
fs/ext4/ext4.h | 6 +++
fs/ext4/fsinfo.c | 97 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/ext4/super.c | 3 ++
4 files changed, 107 insertions(+)
create mode 100644 fs/ext4/fsinfo.c
diff --git a/fs/ext4/Makefile b/fs/ext4/Makefile
index 2e42f47a7f98..ad67812bf7d0 100644
--- a/fs/ext4/Makefile
+++ b/fs/ext4/Makefile
@@ -17,3 +17,4 @@ ext4-$(CONFIG_EXT4_FS_SECURITY) += xattr_security.o
ext4-inode-test-objs += inode-test.o
obj-$(CONFIG_EXT4_KUNIT_TESTS) += ext4-inode-test.o
ext4-$(CONFIG_FS_VERITY) += verity.o
+ext4-$(CONFIG_FSINFO) += fsinfo.o
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 42f5060f3cdf..99a737cf6308 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -43,6 +43,7 @@
#include <linux/fscrypt.h>
#include <linux/fsverity.h>
+#include <linux/fsinfo.h>
#include <linux/compiler.h>
@@ -3233,6 +3234,11 @@ extern const struct inode_operations ext4_file_inode_operations;
extern const struct file_operations ext4_file_operations;
extern loff_t ext4_llseek(struct file *file, loff_t offset, int origin);
+/* fsinfo.c */
+#ifdef CONFIG_FSINFO
+extern int ext4_fsinfo(struct path *path, struct fsinfo_context *ctx);
+#endif
+
/* inline.c */
extern int ext4_get_max_inline_size(struct inode *inode);
extern int ext4_find_inline_data_nolock(struct inode *inode);
diff --git a/fs/ext4/fsinfo.c b/fs/ext4/fsinfo.c
new file mode 100644
index 000000000000..1d4093ef32e7
--- /dev/null
+++ b/fs/ext4/fsinfo.c
@@ -0,0 +1,97 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Filesystem information for ext4
+ *
+ * Copyright (C) 2020 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/mount.h>
+#include "ext4.h"
+
+static int ext4_fsinfo_supports(struct path *path, struct fsinfo_context *ctx)
+{
+ struct fsinfo_supports *p = ctx->buffer;
+ struct inode *inode = d_inode(path->dentry);
+ struct ext4_inode_info *ei = EXT4_I(inode);
+ struct ext4_inode *raw_inode;
+ u32 flags;
+
+ fsinfo_generic_supports(path, ctx);
+ p->stx_attributes |= (STATX_ATTR_APPEND |
+ STATX_ATTR_COMPRESSED |
+ STATX_ATTR_ENCRYPTED |
+ STATX_ATTR_IMMUTABLE |
+ STATX_ATTR_NODUMP |
+ STATX_ATTR_VERITY);
+ if (EXT4_FITS_IN_INODE(raw_inode, ei, i_crtime))
+ p->stx_mask |= STATX_BTIME;
+
+ flags = EXT4_FL_USER_VISIBLE;
+ if (S_ISREG(inode->i_mode))
+ flags &= ~EXT4_PROJINHERIT_FL;
+ p->fs_ioc_getflags = flags;
+ flags &= EXT4_FL_USER_MODIFIABLE;
+ p->fs_ioc_setflags_set = flags;
+ p->fs_ioc_setflags_clear = flags;
+
+ p->fs_ioc_fsgetxattr_xflags = EXT4_FL_XFLAG_VISIBLE;
+ p->fs_ioc_fssetxattr_xflags_set = EXT4_FL_XFLAG_VISIBLE;
+ p->fs_ioc_fssetxattr_xflags_clear = EXT4_FL_XFLAG_VISIBLE;
+ return sizeof(*p);
+}
+
+static int ext4_fsinfo_features(struct path *path, struct fsinfo_context *ctx)
+{
+ struct fsinfo_features *p = ctx->buffer;
+ struct super_block *sb = path->dentry->d_sb;
+ struct inode *inode = d_inode(path->dentry);
+ struct ext4_inode_info *ei = EXT4_I(inode);
+ struct ext4_inode *raw_inode;
+
+ fsinfo_generic_features(path, ctx);
+ fsinfo_set_unix_features(p);
+ fsinfo_set_feature(p, FSINFO_FEAT_VOLUME_UUID);
+ fsinfo_set_feature(p, FSINFO_FEAT_VOLUME_NAME);
+ fsinfo_set_feature(p, FSINFO_FEAT_O_SYNC);
+ fsinfo_set_feature(p, FSINFO_FEAT_O_DIRECT);
+ fsinfo_set_feature(p, FSINFO_FEAT_ADV_LOCKS);
+
+ if (test_opt(sb, XATTR_USER))
+ fsinfo_set_feature(p, FSINFO_FEAT_XATTRS);
+ if (ext4_has_feature_journal(sb))
+ fsinfo_set_feature(p, FSINFO_FEAT_JOURNAL);
+ if (ext4_has_feature_casefold(sb))
+ fsinfo_set_feature(p, FSINFO_FEAT_NAME_CASE_INDEP);
+
+ if (sb->s_flags & SB_I_VERSION &&
+ !test_opt2(sb, HURD_COMPAT) &&
+ EXT4_INODE_SIZE(sb) > EXT4_GOOD_OLD_INODE_SIZE) {
+ fsinfo_set_feature(p, FSINFO_FEAT_IVER_DATA_CHANGE);
+ fsinfo_set_feature(p, FSINFO_FEAT_IVER_MONO_INCR);
+ }
+
+ if (EXT4_FITS_IN_INODE(raw_inode, ei, i_crtime))
+ fsinfo_set_feature(p, FSINFO_FEAT_HAS_BTIME);
+ return sizeof(*p);
+}
+
+static int ext4_fsinfo_get_volume_name(struct path *path, struct fsinfo_context *ctx)
+{
+ const struct ext4_sb_info *sbi = EXT4_SB(path->mnt->mnt_sb);
+ const struct ext4_super_block *es = sbi->s_es;
+
+ memcpy(ctx->buffer, es->s_volume_name, sizeof(es->s_volume_name));
+ return strlen(ctx->buffer) + 1;
+}
+
+static const struct fsinfo_attribute ext4_fsinfo_attributes[] = {
+ FSINFO_VSTRUCT (FSINFO_ATTR_SUPPORTS, ext4_fsinfo_supports),
+ FSINFO_VSTRUCT (FSINFO_ATTR_FEATURES, ext4_fsinfo_features),
+ FSINFO_STRING (FSINFO_ATTR_VOLUME_NAME, ext4_fsinfo_get_volume_name),
+ {}
+};
+
+int ext4_fsinfo(struct path *path, struct fsinfo_context *ctx)
+{
+ return fsinfo_get_attribute(path, ctx, ext4_fsinfo_attributes);
+}
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 330957ed1f05..47f349620176 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1481,6 +1481,9 @@ static const struct super_operations ext4_sops = {
.freeze_fs = ext4_freeze,
.unfreeze_fs = ext4_unfreeze,
.statfs = ext4_statfs,
+#ifdef CONFIG_FSINFO
+ .fsinfo = ext4_fsinfo,
+#endif
.remount_fs = ext4_remount,
.show_options = ext4_show_options,
#ifdef CONFIG_QUOTA
^ permalink raw reply related
* [PATCH 13/18] fsinfo: Add support for AFS [ver #21]
From: David Howells @ 2020-08-03 13:38 UTC (permalink / raw)
To: viro
Cc: dhowells, torvalds, raven, mszeredi, christian, jannh,
darrick.wong, kzak, jlayton, linux-api, linux-fsdevel,
linux-security-module, linux-kernel
In-Reply-To: <159646178122.1784947.11705396571718464082.stgit@warthog.procyon.org.uk>
Add fsinfo support to the AFS filesystem. This allows the export of server
lists, amongst other things, which is necessary to implement some of the
AFS 'fs' command set, such as "checkservers", "getserverprefs" and
"whereis".
Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/afs/internal.h | 1
fs/afs/super.c | 216 +++++++++++++++++++++++++++++++++++++++++++
include/uapi/linux/fsinfo.h | 15 +++
samples/vfs/test-fsinfo.c | 49 ++++++++++
4 files changed, 279 insertions(+), 2 deletions(-)
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 792ac711985e..e775340c23c1 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -225,6 +225,7 @@ struct afs_super_info {
struct afs_volume *volume; /* volume record */
enum afs_flock_mode flock_mode:8; /* File locking emulation mode */
bool dyn_root; /* True if dynamic root */
+ bool autocell; /* True if autocell */
};
static inline struct afs_super_info *AFS_FS_S(struct super_block *sb)
diff --git a/fs/afs/super.c b/fs/afs/super.c
index b552357b1d13..6fe7b8a57869 100644
--- a/fs/afs/super.c
+++ b/fs/afs/super.c
@@ -26,9 +26,13 @@
#include <linux/sched.h>
#include <linux/nsproxy.h>
#include <linux/magic.h>
+#include <linux/fsinfo.h>
#include <net/net_namespace.h>
#include "internal.h"
+#ifdef CONFIG_FSINFO
+static int afs_fsinfo(struct path *path, struct fsinfo_context *ctx);
+#endif
static void afs_i_init_once(void *foo);
static void afs_kill_super(struct super_block *sb);
static struct inode *afs_alloc_inode(struct super_block *sb);
@@ -54,6 +58,9 @@ int afs_net_id;
static const struct super_operations afs_super_ops = {
.statfs = afs_statfs,
+#ifdef CONFIG_FSINFO
+ .fsinfo = afs_fsinfo,
+#endif
.alloc_inode = afs_alloc_inode,
.drop_inode = afs_drop_inode,
.destroy_inode = afs_destroy_inode,
@@ -193,7 +200,7 @@ static int afs_show_options(struct seq_file *m, struct dentry *root)
if (as->dyn_root)
seq_puts(m, ",dyn");
- if (test_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(d_inode(root))->flags))
+ if (as->autocell)
seq_puts(m, ",autocell");
switch (as->flock_mode) {
case afs_flock_mode_unset: break;
@@ -470,7 +477,7 @@ static int afs_fill_super(struct super_block *sb, struct afs_fs_context *ctx)
if (IS_ERR(inode))
return PTR_ERR(inode);
- if (ctx->autocell || as->dyn_root)
+ if (as->autocell || as->dyn_root)
set_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(inode)->flags);
ret = -ENOMEM;
@@ -512,6 +519,8 @@ static struct afs_super_info *afs_alloc_sbi(struct fs_context *fc)
as->volume = afs_get_volume(ctx->volume,
afs_volume_trace_get_alloc_sbi);
}
+ if (ctx->autocell)
+ as->autocell = true;
}
return as;
}
@@ -771,3 +780,206 @@ static int afs_statfs(struct dentry *dentry, struct kstatfs *buf)
op->ops = &afs_get_volume_status_operation;
return afs_do_sync_operation(op);
}
+
+#ifdef CONFIG_FSINFO
+static const struct fsinfo_timestamp_info afs_timestamp_info = {
+ .atime = {
+ .minimum = 0,
+ .maximum = UINT_MAX,
+ .gran_mantissa = 1,
+ .gran_exponent = 0,
+ },
+ .mtime = {
+ .minimum = 0,
+ .maximum = UINT_MAX,
+ .gran_mantissa = 1,
+ .gran_exponent = 0,
+ },
+ .ctime = {
+ .minimum = 0,
+ .maximum = UINT_MAX,
+ .gran_mantissa = 1,
+ .gran_exponent = 0,
+ },
+ .btime = {
+ .minimum = 0,
+ .maximum = UINT_MAX,
+ .gran_mantissa = 1,
+ .gran_exponent = 0,
+ },
+};
+
+static int afs_fsinfo_get_timestamp(struct path *path, struct fsinfo_context *ctx)
+{
+ struct fsinfo_timestamp_info *tsinfo = ctx->buffer;
+ *tsinfo = afs_timestamp_info;
+ return sizeof(*tsinfo);
+}
+
+static int afs_fsinfo_get_limits(struct path *path, struct fsinfo_context *ctx)
+{
+ struct fsinfo_limits *lim = ctx->buffer;
+
+ lim->max_file_size.hi = 0;
+ lim->max_file_size.lo = MAX_LFS_FILESIZE;
+ /* Inode numbers can be 96-bit on YFS, but that's hard to determine. */
+ lim->max_ino.hi = 0;
+ lim->max_ino.lo = UINT_MAX;
+ lim->max_hard_links = UINT_MAX;
+ lim->max_uid = UINT_MAX;
+ lim->max_gid = UINT_MAX;
+ lim->max_filename_len = AFSNAMEMAX - 1;
+ lim->max_symlink_len = AFSPATHMAX - 1;
+ return sizeof(*lim);
+}
+
+static int afs_fsinfo_get_supports(struct path *path, struct fsinfo_context *ctx)
+{
+ struct fsinfo_supports *p = ctx->buffer;
+
+ p->stx_mask = (STATX_TYPE | STATX_MODE |
+ STATX_NLINK |
+ STATX_UID | STATX_GID |
+ STATX_MTIME | STATX_INO |
+ STATX_SIZE);
+ p->stx_attributes = STATX_ATTR_AUTOMOUNT;
+ return sizeof(*p);
+}
+
+static int afs_fsinfo_get_features(struct path *path, struct fsinfo_context *ctx)
+{
+ struct fsinfo_features *p = ctx->buffer;
+
+ fsinfo_set_feature(p, FSINFO_FEAT_IS_NETWORK_FS);
+ fsinfo_set_feature(p, FSINFO_FEAT_AUTOMOUNTS);
+ fsinfo_set_feature(p, FSINFO_FEAT_ADV_LOCKS);
+ fsinfo_set_feature(p, FSINFO_FEAT_UIDS);
+ fsinfo_set_feature(p, FSINFO_FEAT_GIDS);
+ fsinfo_set_feature(p, FSINFO_FEAT_VOLUME_ID);
+ fsinfo_set_feature(p, FSINFO_FEAT_VOLUME_NAME);
+ fsinfo_set_feature(p, FSINFO_FEAT_IVER_MONO_INCR);
+ fsinfo_set_feature(p, FSINFO_FEAT_SYMLINKS);
+ fsinfo_set_feature(p, FSINFO_FEAT_HARD_LINKS_1DIR);
+ fsinfo_set_feature(p, FSINFO_FEAT_HAS_MTIME);
+ fsinfo_set_feature(p, FSINFO_FEAT_HAS_INODE_NUMBERS);
+ return sizeof(*p);
+}
+
+static int afs_dyn_fsinfo_get_features(struct path *path, struct fsinfo_context *ctx)
+{
+ struct fsinfo_features *p = ctx->buffer;
+
+ fsinfo_set_feature(p, FSINFO_FEAT_IS_AUTOMOUNTER_FS);
+ fsinfo_set_feature(p, FSINFO_FEAT_AUTOMOUNTS);
+ return sizeof(*p);
+}
+
+static int afs_fsinfo_get_volume_name(struct path *path, struct fsinfo_context *ctx)
+{
+ struct afs_super_info *as = AFS_FS_S(path->dentry->d_sb);
+ struct afs_volume *volume = as->volume;
+
+ return fsinfo_opaque(volume->name, ctx, volume->name_len + 1);
+}
+
+static int afs_fsinfo_get_cell_name(struct path *path, struct fsinfo_context *ctx)
+{
+ struct afs_super_info *as = AFS_FS_S(path->dentry->d_sb);
+ struct afs_cell *cell = as->cell;
+
+ return fsinfo_opaque(cell->name, ctx, cell->name_len + 1);
+}
+
+static int afs_fsinfo_get_server_name(struct path *path, struct fsinfo_context *ctx)
+{
+ struct afs_server_list *slist;
+ struct afs_super_info *as = AFS_FS_S(path->dentry->d_sb);
+ struct afs_volume *volume = as->volume;
+ struct afs_server *server;
+ int ret = -ENODATA;
+
+ read_lock(&volume->servers_lock);
+ slist = volume->servers;
+ if (slist) {
+ if (ctx->Nth < slist->nr_servers) {
+ server = slist->servers[ctx->Nth].server;
+ ret = sprintf(ctx->buffer, "%pU", &server->uuid) + 1;
+ }
+ }
+
+ read_unlock(&volume->servers_lock);
+ return ret;
+}
+
+static int afs_fsinfo_get_server_address(struct path *path, struct fsinfo_context *ctx)
+{
+ struct fsinfo_afs_server_address *p = ctx->buffer;
+ struct afs_server_list *slist;
+ struct afs_super_info *as = AFS_FS_S(path->dentry->d_sb);
+ struct afs_addr_list *alist;
+ struct afs_volume *volume = as->volume;
+ struct afs_server *server;
+ struct afs_net *net = afs_d2net(path->dentry);
+ unsigned int i;
+ int ret = -ENODATA;
+
+ read_lock(&volume->servers_lock);
+ slist = afs_get_serverlist(volume->servers);
+ read_unlock(&volume->servers_lock);
+
+ if (ctx->Nth >= slist->nr_servers)
+ goto put_slist;
+ server = slist->servers[ctx->Nth].server;
+
+ read_lock(&server->fs_lock);
+ alist = afs_get_addrlist(rcu_dereference_protected(
+ server->addresses,
+ lockdep_is_held(&server->fs_lock)));
+ read_unlock(&server->fs_lock);
+ if (!alist)
+ goto put_slist;
+
+ ret = alist->nr_addrs * sizeof(*p);
+ if (ret <= ctx->buf_size) {
+ for (i = 0; i < alist->nr_addrs; i++)
+ memcpy(&p[i].address, &alist->addrs[i],
+ sizeof(struct sockaddr_rxrpc));
+ }
+
+ afs_put_addrlist(alist);
+put_slist:
+ afs_put_serverlist(net, slist);
+ return ret;
+}
+
+static const struct fsinfo_attribute afs_fsinfo_attributes[] = {
+ FSINFO_VSTRUCT (FSINFO_ATTR_TIMESTAMP_INFO, afs_fsinfo_get_timestamp),
+ FSINFO_VSTRUCT (FSINFO_ATTR_LIMITS, afs_fsinfo_get_limits),
+ FSINFO_VSTRUCT (FSINFO_ATTR_SUPPORTS, afs_fsinfo_get_supports),
+ FSINFO_VSTRUCT (FSINFO_ATTR_FEATURES, afs_fsinfo_get_features),
+ FSINFO_STRING (FSINFO_ATTR_VOLUME_NAME, afs_fsinfo_get_volume_name),
+ FSINFO_STRING (FSINFO_ATTR_AFS_CELL_NAME, afs_fsinfo_get_cell_name),
+ FSINFO_STRING_N (FSINFO_ATTR_AFS_SERVER_NAME, afs_fsinfo_get_server_name),
+ FSINFO_LIST_N (FSINFO_ATTR_AFS_SERVER_ADDRESSES, afs_fsinfo_get_server_address),
+ {}
+};
+
+static const struct fsinfo_attribute afs_dyn_fsinfo_attributes[] = {
+ FSINFO_VSTRUCT(FSINFO_ATTR_TIMESTAMP_INFO, afs_fsinfo_get_timestamp),
+ FSINFO_VSTRUCT(FSINFO_ATTR_FEATURES, afs_dyn_fsinfo_get_features),
+ {}
+};
+
+static int afs_fsinfo(struct path *path, struct fsinfo_context *ctx)
+{
+ struct afs_super_info *as = AFS_FS_S(path->dentry->d_sb);
+ int ret;
+
+ if (as->dyn_root)
+ ret = fsinfo_get_attribute(path, ctx, afs_dyn_fsinfo_attributes);
+ else
+ ret = fsinfo_get_attribute(path, ctx, afs_fsinfo_attributes);
+ return ret;
+}
+
+#endif /* CONFIG_FSINFO */
diff --git a/include/uapi/linux/fsinfo.h b/include/uapi/linux/fsinfo.h
index b021466dee0f..81329de6905e 100644
--- a/include/uapi/linux/fsinfo.h
+++ b/include/uapi/linux/fsinfo.h
@@ -38,6 +38,10 @@
#define FSINFO_ATTR_MOUNT_TOPOLOGY 0x204 /* Mount object topology */
#define FSINFO_ATTR_MOUNT_CHILDREN 0x205 /* Children of this mount (list) */
+#define FSINFO_ATTR_AFS_CELL_NAME 0x300 /* AFS cell name (string) */
+#define FSINFO_ATTR_AFS_SERVER_NAME 0x301 /* Name of the Nth server (string) */
+#define FSINFO_ATTR_AFS_SERVER_ADDRESSES 0x302 /* List of addresses of the Nth server */
+
/*
* Optional fsinfo() parameter structure.
*
@@ -309,4 +313,15 @@ struct fsinfo_volume_uuid {
#define FSINFO_ATTR_VOLUME_UUID__STRUCT struct fsinfo_volume_uuid
+/*
+ * Information struct for fsinfo(FSINFO_ATTR_AFS_SERVER_ADDRESSES).
+ *
+ * Get the addresses of the Nth server for a network filesystem.
+ */
+struct fsinfo_afs_server_address {
+ struct __kernel_sockaddr_storage address;
+};
+
+#define FSINFO_ATTR_AFS_SERVER_ADDRESSES__STRUCT struct fsinfo_afs_server_address
+
#endif /* _UAPI_LINUX_FSINFO_H */
diff --git a/samples/vfs/test-fsinfo.c b/samples/vfs/test-fsinfo.c
index 620a02477aa8..374825ab85b0 100644
--- a/samples/vfs/test-fsinfo.c
+++ b/samples/vfs/test-fsinfo.c
@@ -24,6 +24,7 @@
#include <linux/mount.h>
#include <sys/stat.h>
#include <arpa/inet.h>
+#include <linux/rxrpc.h>
#ifndef __NR_fsinfo
#define __NR_fsinfo -1
@@ -364,6 +365,50 @@ static void dump_fsinfo_generic_mount_children(void *reply, unsigned int size)
(unsigned long long)r->mnt_notify_sum, mp);
}
+static void dump_afs_fsinfo_server_address(void *reply, unsigned int size)
+{
+ struct fsinfo_afs_server_address *f = reply;
+ struct sockaddr_storage *ss = (struct sockaddr_storage *)&f->address;
+ struct sockaddr_rxrpc *srx;
+ struct sockaddr_in6 *sin6;
+ struct sockaddr_in *sin;
+ char proto[32], buf[1024];
+
+ if (ss->ss_family == AF_RXRPC) {
+ srx = (struct sockaddr_rxrpc *)ss;
+ printf("%5u ", srx->srx_service);
+ switch (srx->transport_type) {
+ case SOCK_DGRAM:
+ sprintf(proto, "udp");
+ break;
+ case SOCK_STREAM:
+ sprintf(proto, "tcp");
+ break;
+ default:
+ sprintf(proto, "%3u", srx->transport_type);
+ break;
+ }
+ ss = (struct sockaddr_storage *)&srx->transport;
+ }
+
+ switch (ss->ss_family) {
+ case AF_INET:
+ sin = (struct sockaddr_in *)ss;
+ if (!inet_ntop(AF_INET, &sin->sin_addr, buf, sizeof(buf)))
+ break;
+ printf("%5u/%s %s\n", ntohs(sin->sin_port), proto, buf);
+ return;
+ case AF_INET6:
+ sin6 = (struct sockaddr_in6 *)ss;
+ if (!inet_ntop(AF_INET6, &sin6->sin6_addr, buf, sizeof(buf)))
+ break;
+ printf("%5u/%s %s\n", ntohs(sin6->sin6_port), proto, buf);
+ return;
+ }
+
+ printf("family=%u\n", ss->ss_family);
+}
+
static void dump_string(void *reply, unsigned int size)
{
char *s = reply, *p;
@@ -447,6 +492,10 @@ static const struct fsinfo_attribute fsinfo_attributes[] = {
FSINFO_STRING_N (FSINFO_ATTR_MOUNT_POINT, string),
FSINFO_STRING_N (FSINFO_ATTR_MOUNT_POINT_FULL, string),
FSINFO_LIST (FSINFO_ATTR_MOUNT_CHILDREN, fsinfo_generic_mount_children),
+
+ FSINFO_STRING (FSINFO_ATTR_AFS_CELL_NAME, string),
+ FSINFO_STRING (FSINFO_ATTR_AFS_SERVER_NAME, string),
+ FSINFO_LIST_N (FSINFO_ATTR_AFS_SERVER_ADDRESSES, afs_fsinfo_server_address),
{}
};
^ permalink raw reply related
* [PATCH 12/18] fsinfo: Add API documentation [ver #21]
From: David Howells @ 2020-08-03 13:38 UTC (permalink / raw)
To: viro
Cc: dhowells, torvalds, raven, mszeredi, christian, jannh,
darrick.wong, kzak, jlayton, linux-api, linux-fsdevel,
linux-security-module, linux-kernel
In-Reply-To: <159646178122.1784947.11705396571718464082.stgit@warthog.procyon.org.uk>
Add API documentation for fsinfo.
Signed-off-by: David Howells <dhowells@redhat.com>
---
Documentation/filesystems/fsinfo.rst | 574 ++++++++++++++++++++++++++++++++++
1 file changed, 574 insertions(+)
create mode 100644 Documentation/filesystems/fsinfo.rst
diff --git a/Documentation/filesystems/fsinfo.rst b/Documentation/filesystems/fsinfo.rst
new file mode 100644
index 000000000000..65d88e5a36bc
--- /dev/null
+++ b/Documentation/filesystems/fsinfo.rst
@@ -0,0 +1,574 @@
+============================
+Filesystem Information Query
+============================
+
+The fsinfo() system call allows the querying of filesystem and filesystem
+security information beyond what stat(), statx() and statfs() can obtain. It
+does not require a file to be opened as does ioctl().
+
+fsinfo() may be called with a path, with open file descriptor or a with a mount
+object identifier.
+
+The fsinfo() system call needs to be configured on by enabling:
+
+ "File systems"/"Enable the fsinfo() system call" (CONFIG_FSINFO)
+
+This document has the following sections:
+
+.. contents:: :local:
+
+
+Overview
+========
+
+The fsinfo() system call retrieves one of a number of attributes, the IDs of
+which can be found in include/uapi/linux/fsinfo.h::
+
+ FSINFO_ATTR_STATFS - statfs()-style state
+ FSINFO_ATTR_IDS - Filesystem IDs
+ FSINFO_ATTR_LIMITS - Filesystem limits
+ ...
+ FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO - Information about an attribute
+ FSINFO_ATTR_FSINFO_ATTRIBUTES - List of available attributes
+ ...
+ FSINFO_ATTR_MOUNT_INFO - Information about the mount topology
+ ...
+
+Each attribute can have zero or more values, which can be of one of the
+following types:
+
+ * ``FSINFO_TYPE_VSTRUCT``. This is a structure with a version-dependent
+ length. New versions of the kernel may append more fields, though they are
+ not permitted to remove or replace old ones.
+
+ Older applications, expecting an older version of the field, can ask for a
+ shorter struct and will only get the fields they requested; newer
+ applications running on an older kernel will get the extra fields they
+ requested filled with zeros. Either way, the system call returns the size
+ of the internal struct, regardless of how much data it returned.
+
+ This allows for struct-type fields to be extended in future.
+
+ * ``FSINFO_TYPE_STRING``. This is a variable-length string of up to INT_MAX
+ characters (no NUL character is included). The returned string will be
+ truncated if the output buffer is too small. The total size of the string
+ is returned, regardless of any truncation.
+
+ * ``FSINFO_TYPE_OPAQUE``. This is a variable-length blob of indeterminate
+ structure. It may be up to INT_MAX bytes in size.
+
+ * ``FSINFO_TYPE_LIST``. This is a variable-length list of fixed-size
+ structures. The element size may not vary over time, so the element format
+ must be designed with care. The maximum length is INT_MAX bytes, though
+ this depends on the kernel being able to allocate an internal buffer large
+ enough.
+
+Value type is an inherent propery of an attribute and all the values of an
+attribute must be of that type. Each attribute can have a single value, a
+sequence of values or a sequence-of-sequences of values.
+
+
+Filesystem API
+==============
+
+If the filesystem wishes to override the generic queryable attributes or
+provide queryable attributes of its own, it should define a handler function
+and point the appropriate superblock op to it::
+
+ int (*fsinfo)(struct path *path, struct fsinfo_context *ctx);
+
+The core calls this function to see if it wants to handle the attribute. For
+each table of attibutes it has (and it can have more than one), it should
+call::
+
+ int fsinfo_get_attribute(struct path *path, struct fsinfo_context *ctx,
+ const struct fsinfo_attribute *attrs);
+
+to scan the table to see if the requested one is in there. This function also
+handles determining the size of struct attributes, enumerating attributes for
+the FSINFO_ATTR_FSINFO_ATTRIBUTES and querying information about an attribute
+for FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO.
+
+If it doesn't want to handle the function, -EOPNOTSUPP should be returned. The
+core will then examine the generic attribute table.
+
+
+Attribute Table
+---------------
+
+An attribute table is a sequence of ``struct fsinfo_attribute`` terminated with
+a blank entry. Entries can be created with a set of helper macros::
+
+ FSINFO_VSTRUCT(A,G)
+ FSINFO_VSTRUCT_N(A,G)
+ FSINFO_VSTRUCT_NM(A,G)
+ FSINFO_STRING(A,G)
+ FSINFO_STRING_N(A,G)
+ FSINFO_STRING_NM(A,G)
+ FSINFO_OPAQUE(A,G)
+ FSINFO_LIST(A,G)
+ FSINFO_LIST_N(A,G)
+
+The names of the macro are a combination of type (vstruct, string, opaque and
+list) and an optional qualifier, if the attribute has N values or N lots of M
+values. ``A`` is the name of the attribute and ``G`` is a function to get a
+value for that attribute.
+
+For vstruct- and list-type attributes, it is expected that there is a macro
+defined with the name ``A##__STRUCT`` that indicates the structure type.
+
+The get function needs to match the following type::
+
+ int (*get)(struct path *path, struct fsinfo_context *ctx);
+
+where "path" indicates the object to be queried and ctx is a context describing
+the parameters and the output buffer. The function should return the total
+size of the data it would like to produce or an error.
+
+
+Context Structure
+-----------------
+
+The context struct looks like::
+
+ struct fsinfo_context {
+ __u32 requested_attr;
+ __u32 Nth;
+ __u32 Mth;
+ bool want_size_only;
+ unsigned int skip;
+ unsigned int usage;
+ unsigned int buf_size;
+ void *buffer;
+ ...
+ };
+
+The fields relevant to the filesystem are as follows:
+
+ * ``requested_attr``
+
+ Which attribute is being requested. EOPNOTSUPP should be returned if the
+ attribute is not supported by the filesystem or the LSM.
+
+ * ``Nth`` and ``Mth``
+
+ Which value of an attribute is being requested.
+
+ For a single-value attribute Nth and Mth will both be 0.
+
+ For a "1D" attribute, Nth will indicate which value and Mth will always
+ be 0. Take, for example, FSINFO_ATTR_SERVER_NAME - for a network
+ filesystem, the superblock will be backed by a number of servers. This will
+ return the name of the Nth server. ENODATA will be returned if Nth goes
+ beyond the end of the array.
+
+ For a "2D" attribute, Mth will indicate the index in the Nth set of values.
+ Take, for example, an attribute for a network filesystems that returns
+ server addresses - each server may have one or more addresses. This could
+ return the Mth address of the Nth server. ENODATA should be returned if the
+ Nth set doesn't exist or the Mth element of the Nth set doesn't exist.
+
+ * ``want_size_only``
+
+ Is set to true if the caller only wants the size of the value so that the
+ get function doesn't have to make expensive calculations or calls to
+ retrieve the value.
+
+ * ``skip``
+
+ This indicates how far into the buffer the data to be returned starts. This
+ can be used to trim the front off the buffer or to handle backward-filling.
+
+ * ``usage``
+
+ This indicates how much of the buffer has been used so far for an list or
+ opaque type attribute. This is updated by the fsinfo_note_param*()
+ functions.
+
+ * ``buf_size``
+
+ This indicates the current size of the buffer. For the list type and the
+ opaque type this will be increased if the current buffer won't hold the
+ value and the filesystem will be called again.
+
+ * ``buffer``
+
+ This points to the output buffer. It will be buf_size in size and will be
+ resized if the returned size is larger than this.
+
+To simplify filesystem code, there will always be at least a minimal buffer
+available if a ->get() method gets called.
+
+
+Helper Functions
+================
+
+The API includes a number of helper functions:
+
+ * ``int fsinfo_string(const char *s, struct fsinfo_context *ctx);``
+
+ This places the specified string into the buffer set in the context. If the
+ string is NULL, the buffer will be left empty.
+
+ * ``int fsinfo_generic_timestamp_info(struct path *, struct fsinfo_context *);``
+ * ``int fsinfo_generic_supports(struct path *, struct fsinfo_context *);``
+ * ``int fsinfo_generic_limits(struct path *, struct fsinfo_context *);``
+
+ These set the generic information for timestamp resolution and range
+ information, supported features and number limits and are called for the
+ corresponding attributes if the filesystem doesn't override them.
+
+ If the filesystem does override them, it can call the above functions and
+ then amend the results.
+
+ * ``void fsinfo_set_feature(struct fsinfo_features *ft,
+ enum fsinfo_feature feature);``
+
+ This function sets a feature flag.
+
+ * ``void fsinfo_clear_feature(struct fsinfo_features *ft,
+ enum fsinfo_feature feature);``
+
+ This function clears a feature flag.
+
+ * ``void fsinfo_set_unix_features(struct fsinfo_features *ft);``
+
+ Set feature flags appropriate to the features of a standard UNIX filesystem,
+ such as having numeric UIDS and GIDS; allowing the creation of directories,
+ symbolic links, hard links, device files, FIFO and socket files; permitting
+ sparse files; and having access, change and modification times.
+
+
+Attribute Summary
+=================
+
+To summarise the attributes that are defined::
+
+ Symbolic name Type
+ ===================================== ===============
+ FSINFO_ATTR_STATFS vstruct
+ FSINFO_ATTR_IDS vstruct
+ FSINFO_ATTR_LIMITS vstruct
+ FSINFO_ATTR_SUPPORTS vstruct
+ FSINFO_ATTR_TIMESTAMP_INFO vstruct
+ FSINFO_ATTR_VOLUME_ID string
+ FSINFO_ATTR_VOLUME_UUID vstruct
+ FSINFO_ATTR_VOLUME_NAME string
+ FSINFO_ATTR_FEATURES vstruct
+ FSINFO_ATTR_SOURCE string
+ FSINFO_ATTR_CONFIGURATION string
+ FSINFO_ATTR_FS_STATISTICS string
+ FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO N × vstruct
+ FSINFO_ATTR_FSINFO_ATTRIBUTES list
+ FSINFO_ATTR_MOUNT_INFO vstruct
+ FSINFO_ATTR_MOUNT_PATH string
+ FSINFO_ATTR_MOUNT_POINT string
+ FSINFO_ATTR_MOUNT_CHILDREN list
+ FSINFO_ATTR_AFS_CELL_NAME string
+ FSINFO_ATTR_AFS_SERVER_NAME N × string
+ FSINFO_ATTR_AFS_SERVER_ADDRESSES N × list
+
+
+Attribute Catalogue
+===================
+
+A number of the attributes convey information about a filesystem superblock:
+
+ * ``FSINFO_ATTR_STATFS``
+
+ This struct-type attribute gives most of the equivalent data to statfs(),
+ but with all the fields as unconditional 64-bit or 128-bit integers. Note
+ that static data like IDs that don't change are retrieved with
+ FSINFO_ATTR_IDS instead.
+
+ Further, superblock flags (such as MS_RDONLY) are not exposed by this
+ attribute; rather the parameters must be listed and the attributes picked
+ out from that.
+
+ * ``FSINFO_ATTR_IDS``
+
+ This struct-type attribute conveys various identifiers used by the target
+ filesystem. This includes the filesystem name, the NFS filesystem ID, the
+ superblock ID used in notifications, the filesystem magic type number and
+ the primary device ID.
+
+ * ``FSINFO_ATTR_LIMITS``
+
+ This struct-type attribute conveys the limits on various aspects of a
+ filesystem, such as maximum file, symlink and xattr sizes, maxiumm filename
+ and xattr name length, maximum number of symlinks, maximum device major and
+ minor numbers and maximum UID, GID and project ID numbers.
+
+ * ``FSINFO_ATTR_SUPPORTS``
+
+ This struct-type attribute conveys information about the support the
+ filesystem has for various UAPI features of a filesystem. This includes
+ information about which bits are supported in various masks employed by the
+ statx system call, what FS_IOC_* flags are supported by ioctls and what
+ DOS/Windows file attribute flags are supported.
+
+ * ``FSINFO_ATTR_TIMESTAMP_INFO``
+
+ This struct-type attribute conveys information about the resolution and
+ range of the timestamps available in a filesystem. The resolutions are
+ given as a mantissa and exponent (resolution = mantissa * 10^exponent
+ seconds), where the exponent can be negative to indicate a sub-second
+ resolution (-9 being nanoseconds, for example).
+
+ * ``FSINFO_ATTR_VOLUME_ID``
+
+ This is a string-type attribute that conveys the superblock identifier for
+ the volume. By default it will be filled in from the contents of s_id from
+ the superblock. For a block-based filesystem, for example, this might be
+ the name of the primary block device.
+
+ * ``FSINFO_ATTR_VOLUME_UUID``
+
+ This is a struct-type attribute that conveys the UUID identifier for the
+ volume. By default it will be filled in from the contents of s_uuid from
+ the superblock. If this doesn't exist, it will be an entirely zeros.
+
+ * ``FSINFO_ATTR_VOLUME_NAME``
+
+ This is a string-type attribute that conveys the name of the volume. By
+ default it will return EOPNOTSUPP. For a disk-based filesystem, it might
+ convey the partition label; for a network-based filesystem, it might convey
+ the name of the remote volume.
+
+ * ``FSINFO_ATTR_FEATURES``
+
+ This is a special attribute, being a set of single-bit feature flags,
+ formatted as struct-type attribute. The meanings of the feature bits are
+ listed below - see the "Feature Bit Catalogue" section. The feature bits
+ are grouped numerically into bytes, such that features 0-7 are in byte 0,
+ 8-15 are in byte 1, 16-23 in byte 2 and so on.
+
+ Any feature bit that's not supported by the kernel will be set to false if
+ asked for. The highest supported feature is set at the beginning of the
+ structure.
+
+ * ``FSINFO_ATTR_SOURCE``
+ * ``FSINFO_ATTR_CONFIGURATION``
+ * ``FSINFO_ATTR_FS_STATISTICS``
+
+ These attributes return the mountpoint device name (as processed by the
+ filesystem), the superblock configuration (mount) options and the
+ superblock statistics in string form, as presented through a variety
+ of /proc files.
+
+
+Some attributes give information about fsinfo itself:
+
+ * ``FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO``
+
+ This struct-type attribute gives metadata about the attribute with the ID
+ specified by the Nth parameter, including its type, default size and
+ element size.
+
+ * ``FSINFO_ATTR_FSINFO_ATTRIBUTES``
+
+ This list-type attribute gives a list of the attribute IDs available at the
+ point of reference. FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO can then be used to
+ query each attribute.
+
+
+Some attributes give information about mount objects:
+
+ * ``FSINFO_ATTR_MOUNT_INFO``
+
+ This gives information about a particular mount object, including its IDs,
+ its attributes and its event counters.
+
+ * ``FSINFO_ATTR_MOUNT_TOPOLOGY``
+
+ This gives information about a mount object's topological relationships and
+ propagation attributes. This is more expensive inside the kernel than
+ MOUNT_INFO due to the locking requirements, but the mount object's topology
+ change counter can be used to work out if it has changed.
+
+ This does not give a list of the children; use FSINFO_ATTR_MOUNT_CHILDREN
+ for that.
+
+ * ``FSINFO_ATTR_MOUNT_PATH``
+
+ This gives information about the path set by binding a mount, though it may
+ be overridden by the filesystem.
+
+ * ``FSINFO_ATTR_MOUNT_POINT``
+ * ``FSINFO_ATTR_MOUNT_POINT_FULL``
+
+ These give the path to the mount point for a mount object, in the former
+ relative to its parent mount's mount point (limited to chroot) and in the
+ latter as a full path from the chroot.
+
+ * ``FSINFO_ATTR_MOUNT_CHILDREN``
+
+ This gives a list of all the child mounts of the queried mount. This is
+ presented as tuples of { mount ID, mount uniquifier, event counter sum }
+ and includes at the end a tuple representing the queried mount.
+
+
+Finally there are filesystem-specific attributes, e.g.:
+
+ * ``FSINFO_ATTR_AFS_CELL_NAME``
+
+ This is a string-type attribute that retrieves the AFS cell name of the
+ target object.
+
+ * ``FSINFO_ATTR_AFS_SERVER_NAME``
+
+ This is a string-type attribute that conveys the name of the Nth server
+ backing a network-filesystem superblock.
+
+ * ``FSINFO_ATTR_AFS_SERVER_ADDRESSES``
+
+ This is a list-type attribute that conveys the addresses of the Nth server,
+ corresponding to the Nth server returned by FSINFO_ATTR_SERVER_NAME.
+
+
+Feature Bit Catalogue
+=====================
+
+The feature bits convey single true/false assertions about a specific instance
+of a filesystem (ie. a specific superblock). They are accessed using the
+"FSINFO_ATTR_FEATURE" attribute:
+
+ * ``FSINFO_FEAT_IS_KERNEL_FS``
+ * ``FSINFO_FEAT_IS_BLOCK_FS``
+ * ``FSINFO_FEAT_IS_FLASH_FS``
+ * ``FSINFO_FEAT_IS_NETWORK_FS``
+ * ``FSINFO_FEAT_IS_AUTOMOUNTER_FS``
+ * ``FSINFO_FEAT_IS_MEMORY_FS``
+
+ These indicate what kind of filesystem the target is: kernel API (proc),
+ block-based (ext4), flash/nvm-based (jffs2), remote over the network (NFS),
+ local quasi-filesystem that acts as a tray of mountpoints (autofs), plain
+ in-memory filesystem (shmem).
+
+ * ``FSINFO_FEAT_AUTOMOUNTS``
+
+ This indicate if a filesystem may have objects that are automount points.
+
+ * ``FSINFO_FEAT_ADV_LOCKS``
+ * ``FSINFO_FEAT_MAND_LOCKS``
+ * ``FSINFO_FEAT_LEASES``
+
+ These indicate if a filesystem supports advisory locks, mandatory locks or
+ leases.
+
+ * ``FSINFO_FEAT_UIDS``
+ * ``FSINFO_FEAT_GIDS``
+ * ``FSINFO_FEAT_PROJIDS``
+
+ These indicate if a filesystem supports/stores/transports numeric user IDs,
+ group IDs or project IDs. The "FSINFO_ATTR_LIMITS" attribute can be used
+ to find out the upper limits on the IDs values.
+
+ * ``FSINFO_FEAT_STRING_USER_IDS``
+
+ This indicates if a filesystem supports/stores/transports string user
+ identifiers.
+
+ * ``FSINFO_FEAT_GUID_USER_IDS``
+
+ This indicates if a filesystem supports/stores/transports Windows GUIDs as
+ user identifiers (eg. ntfs).
+
+ * ``FSINFO_FEAT_WINDOWS_ATTRS``
+
+ This indicates if a filesystem supports Windows FILE_* attribute bits
+ (eg. cifs, jfs). The "FSINFO_ATTR_SUPPORTS" attribute can be used to find
+ out which windows file attributes are supported by the filesystem.
+
+ * ``FSINFO_FEAT_USER_QUOTAS``
+ * ``FSINFO_FEAT_GROUP_QUOTAS``
+ * ``FSINFO_FEAT_PROJECT_QUOTAS``
+
+ These indicate if a filesystem supports quotas for users, groups or
+ projects.
+
+ * ``FSINFO_FEAT_XATTRS``
+
+ These indicate if a filesystem supports extended attributes. The
+ "FSINFO_ATTR_LIMITS" attribute can be used to find out the upper limits on
+ the supported name and body lengths.
+
+ * ``FSINFO_FEAT_JOURNAL``
+ * ``FSINFO_FEAT_DATA_IS_JOURNALLED``
+
+ These indicate whether the filesystem has a journal and whether data
+ changes are logged to it.
+
+ * ``FSINFO_FEAT_O_SYNC``
+ * ``FSINFO_FEAT_O_DIRECT``
+
+ These indicate whether the filesystem supports the O_SYNC and O_DIRECT
+ flags.
+
+ * ``FSINFO_FEAT_VOLUME_ID``
+ * ``FSINFO_FEAT_VOLUME_UUID``
+ * ``FSINFO_FEAT_VOLUME_NAME``
+ * ``FSINFO_FEAT_VOLUME_FSID``
+
+ These indicate whether ID, UUID, name and FSID identifiers actually exist
+ in the filesystem and thus might be considered persistent.
+
+ * ``FSINFO_FEAT_IVER_ALL_CHANGE``
+ * ``FSINFO_FEAT_IVER_DATA_CHANGE``
+ * ``FSINFO_FEAT_IVER_MONO_INCR``
+
+ These indicate whether i_version in the inode is supported and, if so, what
+ mode it operates in. The first two indicate if it's changed for any data
+ or metadata change, or whether it's only changed for any data changes; the
+ last indicates whether or not it's monotonically increasing for each such
+ change.
+
+ * ``FSINFO_FEAT_HARD_LINKS``
+ * ``FSINFO_FEAT_HARD_LINKS_1DIR``
+
+ These indicate whether the filesystem can have hard links made in it, and
+ whether they can be made between directory or only within the same
+ directory.
+
+ * ``FSINFO_FEAT_DIRECTORIES``
+ * ``FSINFO_FEAT_SYMLINKS``
+ * ``FSINFO_FEAT_DEVICE_FILES``
+ * ``FSINFO_FEAT_UNIX_SPECIALS``
+
+ These indicate whether directories; symbolic links; device files; or pipes
+ and sockets can be made within the filesystem.
+
+ * ``FSINFO_FEAT_RESOURCE_FORKS``
+
+ This indicates if the filesystem supports resource forks.
+
+ * ``FSINFO_FEAT_NAME_CASE_INDEP``
+ * ``FSINFO_FEAT_NAME_NON_UTF8``
+ * ``FSINFO_FEAT_NAME_HAS_CODEPAGE``
+
+ These indicate if the filesystem supports case-independent file names,
+ whether the filenames are non-utf8 (see the "FSINFO_ATTR_NAME_ENCODING"
+ attribute) and whether a codepage is in use to transliterate them (see
+ the "FSINFO_ATTR_NAME_CODEPAGE" attribute).
+
+ * ``FSINFO_FEAT_SPARSE``
+
+ This indicates if a filesystem supports sparse files.
+
+ * ``FSINFO_FEAT_NOT_PERSISTENT``
+
+ This indicates if a filesystem is not persistent.
+
+ * ``FSINFO_FEAT_NO_UNIX_MODE``
+
+ This indicates if a filesystem doesn't support UNIX mode bits (though they
+ may be manufactured from other bits, such as Windows file attribute flags).
+
+ * ``FSINFO_FEAT_HAS_ATIME``
+ * ``FSINFO_FEAT_HAS_BTIME``
+ * ``FSINFO_FEAT_HAS_CTIME``
+ * ``FSINFO_FEAT_HAS_MTIME``
+
+ These indicate which timestamps a filesystem supports (access, birth,
+ change, modify). The range and resolutions can be queried with the
+ "FSINFO_ATTR_TIMESTAMPS" attribute).
^ permalink raw reply related
* [PATCH 11/18] fsinfo: sample: Mount listing program [ver #21]
From: David Howells @ 2020-08-03 13:37 UTC (permalink / raw)
To: viro
Cc: dhowells, torvalds, raven, mszeredi, christian, jannh,
darrick.wong, kzak, jlayton, linux-api, linux-fsdevel,
linux-security-module, linux-kernel
In-Reply-To: <159646178122.1784947.11705396571718464082.stgit@warthog.procyon.org.uk>
Implement a program to demonstrate mount listing using the new fsinfo()
syscall. For example, to dump the tree from mount 21:
# ./test-mntinfo -m 21
MOUNT MOUNT ID CHANGE# AT P DEV TYPE
-------------------------------- ---------- -------- -- - ----- --------
21 21 0 e 4 0:14 sysfs
\_ kernel/security 24 0 e 4 0:8 securityfs
\_ fs/cgroup 28 4 2f 4 0:18 tmpfs
| \_ unified 29 0 e 4 0:19 cgroup2
| \_ systemd 30 0 e 4 0:1a cgroup
| \_ blkio 34 0 e 4 0:1e cgroup
| \_ net_cls,net_prio 35 0 e 4 0:1f cgroup
| \_ perf_event 36 0 e 4 0:20 cgroup
| \_ freezer 37 0 e 4 0:21 cgroup
| \_ devices 38 0 e 4 0:22 cgroup
| \_ cpu,cpuacct 39 0 e 4 0:23 cgroup
| \_ rdma 40 0 e 4 0:24 cgroup
| \_ memory 41 0 e 4 0:25 cgroup
| \_ cpuset 42 0 e 4 0:26 cgroup
| \_ hugetlb 43 0 e 4 0:27 cgroup
\_ fs/pstore 31 0 e 4 0:1b pstore
\_ firmware/efi/efivars 32 0 e 4 0:1c efivarfs
\_ fs/bpf 33 0 e 4 0:1d bpf
\_ kernel/config 92 0 0 4 0:28 configfs
\_ fs/selinux 44 0 0 4 0:11 selinuxfs
\_ kernel/debug 45 1 0 4 0:7 debugfs
Signed-off-by: David Howells <dhowells@redhat.com>
---
samples/vfs/Makefile | 6 +
samples/vfs/test-mntinfo.c | 277 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 282 insertions(+), 1 deletion(-)
create mode 100644 samples/vfs/test-mntinfo.c
diff --git a/samples/vfs/Makefile b/samples/vfs/Makefile
index d63af5106fc2..7bcdd7a2829e 100644
--- a/samples/vfs/Makefile
+++ b/samples/vfs/Makefile
@@ -1,5 +1,9 @@
# SPDX-License-Identifier: GPL-2.0-only
-userprogs := test-fsinfo test-fsmount test-statx
+userprogs := \
+ test-fsinfo \
+ test-fsmount \
+ test-mntinfo \
+ test-statx
always-y := $(userprogs)
userccflags += -I usr/include
diff --git a/samples/vfs/test-mntinfo.c b/samples/vfs/test-mntinfo.c
new file mode 100644
index 000000000000..a706b5e85997
--- /dev/null
+++ b/samples/vfs/test-mntinfo.c
@@ -0,0 +1,277 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Test the fsinfo() system call
+ *
+ * Copyright (C) 2020 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#define _GNU_SOURCE
+#define _ATFILE_SOURCE
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+#include <ctype.h>
+#include <errno.h>
+#include <time.h>
+#include <math.h>
+#include <sys/syscall.h>
+#include <linux/fsinfo.h>
+#include <linux/socket.h>
+#include <linux/fcntl.h>
+#include <sys/stat.h>
+#include <arpa/inet.h>
+
+#ifndef __NR_fsinfo
+#define __NR_fsinfo -1
+#endif
+
+static __attribute__((unused))
+ssize_t fsinfo(int dfd, const char *filename,
+ struct fsinfo_params *params, size_t params_size,
+ void *result_buffer, size_t result_buf_size)
+{
+ return syscall(__NR_fsinfo, dfd, filename,
+ params, params_size,
+ result_buffer, result_buf_size);
+}
+
+static char tree_buf[4096];
+static char bar_buf[4096];
+static unsigned int children_list_interval;
+
+/*
+ * Get an fsinfo attribute in a statically allocated buffer.
+ */
+static void get_attr(unsigned int mnt_id, unsigned int attr, unsigned int Nth,
+ void *buf, size_t buf_size)
+{
+ struct fsinfo_params params = {
+ .flags = FSINFO_FLAGS_QUERY_MOUNT,
+ .request = attr,
+ .Nth = Nth,
+ };
+ char file[32];
+ long ret;
+
+ sprintf(file, "%u", mnt_id);
+
+ memset(buf, 0xbd, buf_size);
+
+ ret = fsinfo(AT_FDCWD, file, ¶ms, sizeof(params), buf, buf_size);
+ if (ret == -1) {
+ fprintf(stderr, "mount-%s: %m\n", file);
+ exit(1);
+ }
+}
+
+/*
+ * Get an fsinfo attribute in a dynamically allocated buffer.
+ */
+static void *get_attr_alloc(unsigned int mnt_id, unsigned int attr,
+ unsigned int Nth, size_t *_size)
+{
+ struct fsinfo_params params = {
+ .flags = FSINFO_FLAGS_QUERY_MOUNT,
+ .request = attr,
+ .Nth = Nth,
+ };
+ size_t buf_size = 4096;
+ char file[32];
+ void *r;
+ long ret;
+
+ sprintf(file, "%u", mnt_id);
+
+ for (;;) {
+ r = malloc(buf_size);
+ if (!r) {
+ perror("malloc");
+ exit(1);
+ }
+ memset(r, 0xbd, buf_size);
+
+ ret = fsinfo(AT_FDCWD, file, ¶ms, sizeof(params), r, buf_size);
+ if (ret == -1) {
+ fprintf(stderr, "mount-%s: %x,%x,%x %m\n",
+ file, params.request, params.Nth, params.Mth);
+ exit(1);
+ }
+
+ if (ret <= buf_size) {
+ *_size = ret;
+ break;
+ }
+ buf_size = (ret + 4096 - 1) & ~(4096 - 1);
+ }
+
+ return r;
+}
+
+/*
+ * Display a mount and then recurse through its children.
+ */
+static void display_mount(unsigned int mnt_id, unsigned int depth, char *path)
+{
+ struct fsinfo_mount_topology top;
+ struct fsinfo_mount_child child;
+ struct fsinfo_mount_info info;
+ struct fsinfo_ids ids;
+ void *children;
+ unsigned int d;
+ size_t ch_size, p_size;
+ char dev[64];
+ int i, n, s;
+
+ get_attr(mnt_id, FSINFO_ATTR_MOUNT_TOPOLOGY, 0, &top, sizeof(top));
+ get_attr(mnt_id, FSINFO_ATTR_MOUNT_INFO, 0, &info, sizeof(info));
+ get_attr(mnt_id, FSINFO_ATTR_IDS, 0, &ids, sizeof(ids));
+ if (depth > 0)
+ printf("%s", tree_buf);
+
+ s = strlen(path);
+ printf("%s", !s ? "\"\"" : path);
+ if (!s)
+ s += 2;
+ s += depth;
+ if (s < 38)
+ s = 38 - s;
+ else
+ s = 1;
+ printf("%*.*s", s, s, "");
+
+ sprintf(dev, "%x:%x", ids.f_dev_major, ids.f_dev_minor);
+ printf("%10u %8llx %2x %x %5s %s",
+ info.mnt_id,
+ (info.mnt_attr_changes +
+ info.mnt_topology_changes +
+ info.mnt_subtree_notifications),
+ info.attr, top.propagation_type,
+ dev, ids.f_fs_name);
+ putchar('\n');
+
+ children = get_attr_alloc(mnt_id, FSINFO_ATTR_MOUNT_CHILDREN, 0, &ch_size);
+ n = ch_size / children_list_interval - 1;
+
+ bar_buf[depth + 1] = '|';
+ if (depth > 0) {
+ tree_buf[depth - 4 + 1] = bar_buf[depth - 4 + 1];
+ tree_buf[depth - 4 + 2] = ' ';
+ }
+
+ tree_buf[depth + 0] = ' ';
+ tree_buf[depth + 1] = '\\';
+ tree_buf[depth + 2] = '_';
+ tree_buf[depth + 3] = ' ';
+ tree_buf[depth + 4] = 0;
+ d = depth + 4;
+
+ memset(&child, 0, sizeof(child));
+ for (i = 0; i < n; i++) {
+ void *p = children + i * children_list_interval;
+
+ if (sizeof(child) >= children_list_interval)
+ memcpy(&child, p, children_list_interval);
+ else
+ memcpy(&child, p, sizeof(child));
+
+ if (i == n - 1)
+ bar_buf[depth + 1] = ' ';
+ path = get_attr_alloc(child.mnt_id, FSINFO_ATTR_MOUNT_POINT,
+ 0, &p_size);
+ display_mount(child.mnt_id, d, path + 1);
+ free(path);
+ }
+
+ free(children);
+ if (depth > 0) {
+ tree_buf[depth - 4 + 1] = '\\';
+ tree_buf[depth - 4 + 2] = '_';
+ }
+ tree_buf[depth] = 0;
+}
+
+/*
+ * Find the ID of whatever is at the nominated path.
+ */
+static unsigned int lookup_mnt_by_path(const char *path)
+{
+ struct fsinfo_mount_info mnt;
+ struct fsinfo_params params = {
+ .flags = FSINFO_FLAGS_QUERY_PATH,
+ .request = FSINFO_ATTR_MOUNT_INFO,
+ };
+
+ if (fsinfo(AT_FDCWD, path, ¶ms, sizeof(params), &mnt, sizeof(mnt)) == -1) {
+ perror(path);
+ exit(1);
+ }
+
+ return mnt.mnt_id;
+}
+
+/*
+ * Determine the element size for the mount child list.
+ */
+static unsigned int query_list_element_size(int mnt_id, unsigned int attr)
+{
+ struct fsinfo_attribute_info attr_info;
+
+ get_attr(mnt_id, FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO, attr,
+ &attr_info, sizeof(attr_info));
+ return attr_info.size;
+}
+
+/*
+ *
+ */
+int main(int argc, char **argv)
+{
+ unsigned int mnt_id;
+ char *path;
+ bool use_mnt_id = false;
+ int opt;
+
+ while ((opt = getopt(argc, argv, "m"))) {
+ switch (opt) {
+ case 'm':
+ use_mnt_id = true;
+ continue;
+ }
+ break;
+ }
+
+ argc -= optind;
+ argv += optind;
+
+ switch (argc) {
+ case 0:
+ mnt_id = lookup_mnt_by_path("/");
+ path = "ROOT";
+ break;
+ case 1:
+ path = argv[0];
+ if (use_mnt_id) {
+ mnt_id = strtoul(argv[0], NULL, 0);
+ break;
+ }
+
+ mnt_id = lookup_mnt_by_path(argv[0]);
+ break;
+ default:
+ printf("Format: test-mntinfo\n");
+ printf("Format: test-mntinfo <path>\n");
+ printf("Format: test-mntinfo -m <mnt_id>\n");
+ exit(2);
+ }
+
+ children_list_interval =
+ query_list_element_size(mnt_id, FSINFO_ATTR_MOUNT_CHILDREN);
+
+ printf("MOUNT MOUNT ID CHANGE# AT P DEV TYPE\n");
+ printf("------------------------------------- ---------- -------- -- - ----- --------\n");
+ display_mount(mnt_id, 0, path);
+ return 0;
+}
^ permalink raw reply related
* [PATCH 10/18] fsinfo: Provide notification overrun handling support [ver #21]
From: David Howells @ 2020-08-03 13:37 UTC (permalink / raw)
To: viro
Cc: dhowells, torvalds, raven, mszeredi, christian, jannh,
darrick.wong, kzak, jlayton, linux-api, linux-fsdevel,
linux-security-module, linux-kernel
In-Reply-To: <159646178122.1784947.11705396571718464082.stgit@warthog.procyon.org.uk>
Provide support for the handling of an overrun in a watch queue. In the
event that an overrun occurs, the watcher needs to be able to find out what
it was that they missed. To this end, previous patches added event
counters to struct mount.
To make them accessible, they can be retrieved using fsinfo() and the
FSINFO_ATTR_MOUNT_INFO attribute.
struct fsinfo_mount_info {
__u64 mnt_unique_id;
__u64 mnt_attr_changes;
__u64 mnt_topology_changes;
__u64 mnt_subtree_notifications;
...
};
There's a uniquifier and some event counters:
(1) mnt_unique_id - This is an effectively non-repeating ID given to each
mount object on creation. This allows the caller to check that the
mount ID didn't get reused (the 32-bit mount ID is more efficient to
look up).
(2) mnt_attr_changes - Count of attribute changes on a mount object.
(3) mnt_topology_changes - Count of alterations to the mount tree that
affected this node.
(4) mnt_subtree_notifications - Count of mount object event notifications
that were generated in the subtree rooted at this node. This excludes
events generated on this node itself and does not include superblock
events.
The counters are also accessible through the FSINFO_ATTR_MOUNT_CHILDREN
attribute, where a list of all the children of a mount can be scanned. The
record returned for each child includes the sum of the counters for that
child. An additional record is added at the end for the queried object and
that also includes the sum of its counters
The mnt_topology_changes counter is also included in
FSINFO_ATTR_MOUNT_TOPOLOGY.
Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/mount_notify.c | 2 ++
fs/namespace.c | 21 +++++++++++++++++++++
include/uapi/linux/fsinfo.h | 7 +++++++
samples/vfs/test-fsinfo.c | 10 ++++++++--
4 files changed, 38 insertions(+), 2 deletions(-)
diff --git a/fs/mount_notify.c b/fs/mount_notify.c
index 57eebae51cb1..57995c27ca88 100644
--- a/fs/mount_notify.c
+++ b/fs/mount_notify.c
@@ -93,6 +93,8 @@ void notify_mount(struct mount *trigger,
n.watch.info = info_flags | watch_sizeof(n);
n.triggered_on = trigger->mnt_unique_id;
+ smp_wmb(); /* See fsinfo_generic_mount_info(). */
+
switch (subtype) {
case NOTIFY_MOUNT_EXPIRY:
case NOTIFY_MOUNT_READONLY:
diff --git a/fs/namespace.c b/fs/namespace.c
index b5c2a3b4f96d..122c12f9512b 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -4282,6 +4282,17 @@ int fsinfo_generic_mount_info(struct path *path, struct fsinfo_context *ctx)
p->mnt_unique_id = m->mnt_unique_id;
p->mnt_id = m->mnt_id;
+#ifdef CONFIG_MOUNT_NOTIFICATIONS
+ p->mnt_subtree_notifications = atomic_long_read(&m->mnt_subtree_notifications);
+ p->mnt_topology_changes = atomic_long_read(&m->mnt_topology_changes);
+ p->mnt_attr_changes = atomic_long_read(&m->mnt_attr_changes);
+#endif
+
+ /* Record the counters before reading the attributes as we're not
+ * holding a lock. Paired with a write barrier in notify_mount().
+ */
+ smp_rmb();
+
flags = READ_ONCE(m->mnt.mnt_flags);
if (flags & MNT_READONLY)
p->attr |= MOUNT_ATTR_RDONLY;
@@ -4319,6 +4330,9 @@ int fsinfo_generic_mount_topology(struct path *path, struct fsinfo_context *ctx)
m = real_mount(path->mnt);
+#ifdef CONFIG_MOUNT_NOTIFICATIONS
+ p->mnt_topology_changes = atomic_long_read(&m->mnt_topology_changes);
+#endif
p->parent_id = m->mnt_parent->mnt_id;
if (path->mnt == root.mnt) {
@@ -4445,6 +4459,13 @@ static void fsinfo_store_mount(struct fsinfo_context *ctx, const struct mount *p
record.mnt_unique_id = p->mnt_unique_id;
record.mnt_id = p->mnt_id;
record.parent_id = is_root ? p->mnt_id : p->mnt_parent->mnt_id;
+
+#ifdef CONFIG_MOUNT_NOTIFICATIONS
+ record.mnt_notify_sum = (atomic_long_read(&p->mnt_attr_changes) +
+ atomic_long_read(&p->mnt_topology_changes) +
+ atomic_long_read(&p->mnt_subtree_notifications));
+#endif
+
memcpy(ctx->buffer + usage, &record, sizeof(record));
}
diff --git a/include/uapi/linux/fsinfo.h b/include/uapi/linux/fsinfo.h
index f0a352b7028e..b021466dee0f 100644
--- a/include/uapi/linux/fsinfo.h
+++ b/include/uapi/linux/fsinfo.h
@@ -100,6 +100,9 @@ struct fsinfo_mount_info {
__u64 mnt_unique_id; /* Kernel-lifetime unique mount ID */
__u32 mnt_id; /* Mount identifier (use with AT_FSINFO_MOUNTID_PATH) */
__u32 attr; /* MOUNT_ATTR_* flags */
+ __u64 mnt_attr_changes; /* Number of attribute changes to this mount. */
+ __u64 mnt_topology_changes; /* Number of topology changes to this mount. */
+ __u64 mnt_subtree_notifications; /* Number of notifications in mount subtree */
};
#define FSINFO_ATTR_MOUNT_INFO__STRUCT struct fsinfo_mount_info
@@ -113,6 +116,7 @@ struct fsinfo_mount_topology {
__u32 dependent_source_id; /* Dependent: source mount group ID */
__u32 dependent_clone_of_id; /* Dependent: ID of mount this was cloned from */
__u32 propagation_type; /* MOUNT_PROPAGATION_* type */
+ __u64 mnt_topology_changes; /* Number of topology changes to this mount. */
};
#define FSINFO_ATTR_MOUNT_TOPOLOGY__STRUCT struct fsinfo_mount_topology
@@ -125,6 +129,9 @@ struct fsinfo_mount_child {
__u64 mnt_unique_id; /* Kernel-lifetime unique mount ID */
__u32 mnt_id; /* Mount identifier (use with AT_FSINFO_MOUNTID_PATH) */
__u32 parent_id; /* Parent mount identifier */
+ __u64 mnt_notify_sum; /* Sum of mnt_attr_changes, mnt_topology_changes and
+ * mnt_subtree_notifications.
+ */
};
#define FSINFO_ATTR_MOUNT_CHILDREN__STRUCT struct fsinfo_mount_child
diff --git a/samples/vfs/test-fsinfo.c b/samples/vfs/test-fsinfo.c
index b7290ea8eb55..620a02477aa8 100644
--- a/samples/vfs/test-fsinfo.c
+++ b/samples/vfs/test-fsinfo.c
@@ -304,6 +304,10 @@ static void dump_fsinfo_generic_mount_info(void *reply, unsigned int size)
printf("\tmnt_uniq: %llx\n", (unsigned long long)r->mnt_unique_id);
printf("\tmnt_id : %x\n", r->mnt_id);
printf("\tattr : %x\n", r->attr);
+ printf("\tevents : attr=%llu topology=%llu subtree=%llu\n",
+ (unsigned long long)r->mnt_attr_changes,
+ (unsigned long long)r->mnt_topology_changes,
+ (unsigned long long)r->mnt_subtree_notifications);
}
static void dump_fsinfo_generic_mount_topology(void *reply, unsigned int size)
@@ -332,6 +336,7 @@ static void dump_fsinfo_generic_mount_topology(void *reply, unsigned int size)
break;
}
+ printf("\tevents : topology=%llu\n", (unsigned long long)r->mnt_topology_changes);
}
static void dump_fsinfo_generic_mount_children(void *reply, unsigned int size)
@@ -354,8 +359,9 @@ static void dump_fsinfo_generic_mount_children(void *reply, unsigned int size)
mp = "<this>";
}
- printf("%8x %16llx %s\n",
- r->mnt_id, (unsigned long long)r->mnt_unique_id, mp);
+ printf("%8x %16llx %10llu %s\n",
+ r->mnt_id, (unsigned long long)r->mnt_unique_id,
+ (unsigned long long)r->mnt_notify_sum, mp);
}
static void dump_string(void *reply, unsigned int size)
^ permalink raw reply related
* [PATCH 09/18] watch_queue: Mount event counters [ver #21]
From: David Howells @ 2020-08-03 13:37 UTC (permalink / raw)
To: viro
Cc: dhowells, torvalds, raven, mszeredi, christian, jannh,
darrick.wong, kzak, jlayton, linux-api, linux-fsdevel,
linux-security-module, linux-kernel
In-Reply-To: <159646178122.1784947.11705396571718464082.stgit@warthog.procyon.org.uk>
Add three event counters to each mount object:
(1) mnt_topology_changes.
Counts the number of changes to the mount tree topology, including
addition of new mount objects, removal of mount objects and mount
objects being moved about.
(2) mnt_attr_changes.
Counts the number of changes to a mount object's attributes, such as
whether or not the device files it contains are interpretable as such.
(3) mnt_subtree_notifications.
Counts the number of events within the mount subtree at this point.
Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/mount.h | 3 +++
fs/mount_notify.c | 4 ++++
2 files changed, 7 insertions(+)
diff --git a/fs/mount.h b/fs/mount.h
index 1037781be055..9758a9fa8f69 100644
--- a/fs/mount.h
+++ b/fs/mount.h
@@ -83,6 +83,9 @@ struct mount {
u64 mnt_unique_id; /* ID unique over lifetime of kernel */
#endif
#ifdef CONFIG_MOUNT_NOTIFICATIONS
+ atomic_long_t mnt_topology_changes; /* Number of topology changes applied */
+ atomic_long_t mnt_attr_changes; /* Number of attribute changes applied */
+ atomic_long_t mnt_subtree_notifications; /* Number of notifications in subtree */
struct watch_list *mnt_watchers; /* Watches on dentries within this mount */
#endif
} __randomize_layout;
diff --git a/fs/mount_notify.c b/fs/mount_notify.c
index d8ba66ed5f77..57eebae51cb1 100644
--- a/fs/mount_notify.c
+++ b/fs/mount_notify.c
@@ -61,6 +61,7 @@ static void post_mount_notification(struct mount *changed,
cursor.dentry = READ_ONCE(mnt->mnt_mountpoint);
mnt = parent;
cursor.mnt = &mnt->mnt;
+ atomic_long_inc(&mnt->mnt_subtree_notifications);
} else {
cursor.dentry = cursor.dentry->d_parent;
}
@@ -96,6 +97,7 @@ void notify_mount(struct mount *trigger,
case NOTIFY_MOUNT_EXPIRY:
case NOTIFY_MOUNT_READONLY:
case NOTIFY_MOUNT_SETATTR:
+ atomic_long_inc(&trigger->mnt_attr_changes);
break;
case NOTIFY_MOUNT_NEW_MOUNT:
@@ -103,6 +105,8 @@ void notify_mount(struct mount *trigger,
case NOTIFY_MOUNT_MOVE_FROM:
case NOTIFY_MOUNT_MOVE_TO:
n.auxiliary_mount = aux->mnt_unique_id;
+ atomic_long_inc(&trigger->mnt_topology_changes);
+ atomic_long_inc(&aux->mnt_topology_changes);
break;
default:
^ permalink raw reply related
* [PATCH 08/18] fsinfo: Allow mount topology and propagation info to be retrieved [ver #21]
From: David Howells @ 2020-08-03 13:37 UTC (permalink / raw)
To: viro
Cc: dhowells, torvalds, raven, mszeredi, christian, jannh,
darrick.wong, kzak, jlayton, linux-api, linux-fsdevel,
linux-security-module, linux-kernel
In-Reply-To: <159646178122.1784947.11705396571718464082.stgit@warthog.procyon.org.uk>
Add a couple of attributes to allow information about the mount topology
and propagation to be retrieved:
(1) FSINFO_ATTR_MOUNT_TOPOLOGY.
Information about a mount's parentage in the mount topology tree and
its propagation attributes.
This has to be collected with the VFS namespace lock held, so it's
separate from FSINFO_ATTR_MOUNT_INFO. The topology change counter
that a subsequent patch will export can be used to work out from the
cheaper _INFO attribute as to whether the more expensive _TOPOLOGY
attribute needs requerying.
MOUNT_PROPAGATION_* flags are added to linux/mount.h for UAPI
consumption. At some point a mount_setattr() system call needs to be
added.
(2) FSINFO_ATTR_MOUNT_CHILDREN.
Information about a mount's children in the mount topology tree.
This is formatted as an array of structures, one for each child and
capped with one for the argument mount (checked after listing all the
children). Each element contains the static IDs of the respective
mount object along with a sum of its change attributes.
Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/fsinfo.c | 2 +
fs/internal.h | 2 +
fs/namespace.c | 94 +++++++++++++++++++++++++++++++++++++++++++
include/uapi/linux/fsinfo.h | 27 ++++++++++++
include/uapi/linux/mount.h | 13 +++++-
samples/vfs/test-fsinfo.c | 55 +++++++++++++++++++++++++
6 files changed, 192 insertions(+), 1 deletion(-)
diff --git a/fs/fsinfo.c b/fs/fsinfo.c
index f276857709ee..0540cce89555 100644
--- a/fs/fsinfo.c
+++ b/fs/fsinfo.c
@@ -291,9 +291,11 @@ static const struct fsinfo_attribute fsinfo_common_attributes[] = {
FSINFO_VSTRUCT_N(FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO, (void *)123UL),
FSINFO_VSTRUCT (FSINFO_ATTR_MOUNT_INFO, fsinfo_generic_mount_info),
+ FSINFO_VSTRUCT (FSINFO_ATTR_MOUNT_TOPOLOGY, fsinfo_generic_mount_topology),
FSINFO_STRING (FSINFO_ATTR_MOUNT_PATH, fsinfo_generic_seq_read),
FSINFO_STRING (FSINFO_ATTR_MOUNT_POINT, fsinfo_generic_mount_point),
FSINFO_STRING (FSINFO_ATTR_MOUNT_POINT_FULL, fsinfo_generic_mount_point_full),
+ FSINFO_LIST (FSINFO_ATTR_MOUNT_CHILDREN, fsinfo_generic_mount_children),
{}
};
diff --git a/fs/internal.h b/fs/internal.h
index a56008b7f3ec..cb5edcc7125a 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -98,8 +98,10 @@ extern void dissolve_on_fput(struct vfsmount *);
extern int lookup_mount_object(struct path *, unsigned int, struct path *);
extern int fsinfo_generic_mount_source(struct path *, struct fsinfo_context *);
extern int fsinfo_generic_mount_info(struct path *, struct fsinfo_context *);
+extern int fsinfo_generic_mount_topology(struct path *, struct fsinfo_context *);
extern int fsinfo_generic_mount_point(struct path *, struct fsinfo_context *);
extern int fsinfo_generic_mount_point_full(struct path *, struct fsinfo_context *);
+extern int fsinfo_generic_mount_children(struct path *, struct fsinfo_context *);
/*
* fs_struct.c
diff --git a/fs/namespace.c b/fs/namespace.c
index c196af35d39d..b5c2a3b4f96d 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -4303,6 +4303,54 @@ int fsinfo_generic_mount_info(struct path *path, struct fsinfo_context *ctx)
return sizeof(*p);
}
+/*
+ * Retrieve information about the topology at the nominated mount and
+ * its propogation attributes.
+ */
+int fsinfo_generic_mount_topology(struct path *path, struct fsinfo_context *ctx)
+{
+ struct fsinfo_mount_topology *p = ctx->buffer;
+ struct mount *m;
+ struct path root;
+
+ get_fs_root(current->fs, &root);
+
+ namespace_lock();
+
+ m = real_mount(path->mnt);
+
+ p->parent_id = m->mnt_parent->mnt_id;
+
+ if (path->mnt == root.mnt) {
+ p->parent_id = m->mnt_id;
+ } else {
+ rcu_read_lock();
+ if (!are_paths_connected(&root, path))
+ p->parent_id = m->mnt_id;
+ rcu_read_unlock();
+ }
+
+ if (IS_MNT_SHARED(m)) {
+ p->shared_group_id = m->mnt_group_id;
+ p->propagation_type |= MOUNT_PROPAGATION_SHARED;
+ } else if (IS_MNT_SLAVE(m)) {
+ int source = m->mnt_master->mnt_group_id;
+ int from = get_dominating_id(m, &root);
+ p->dependent_source_id = source;
+ if (from && from != source)
+ p->dependent_clone_of_id = from;
+ p->propagation_type |= MOUNT_PROPAGATION_DEPENDENT;
+ } else if (IS_MNT_UNBINDABLE(m)) {
+ p->propagation_type |= MOUNT_PROPAGATION_UNBINDABLE;
+ } else {
+ p->propagation_type |= MOUNT_PROPAGATION_PRIVATE;
+ }
+
+ namespace_unlock();
+ path_put(&root);
+ return sizeof(*p);
+}
+
/*
* Return the path of this mount relative to its parent and clipped to
* the current chroot.
@@ -4379,4 +4427,50 @@ int fsinfo_generic_mount_point_full(struct path *path, struct fsinfo_context *ct
return (ctx->buffer + ctx->buf_size) - p;
}
+/*
+ * Store a mount record into the fsinfo buffer.
+ */
+static void fsinfo_store_mount(struct fsinfo_context *ctx, const struct mount *p,
+ bool is_root)
+{
+ struct fsinfo_mount_child record = {};
+ unsigned int usage = ctx->usage;
+
+ if (ctx->usage >= INT_MAX)
+ return;
+ ctx->usage = usage + sizeof(record);
+ if (!ctx->buffer || ctx->usage > ctx->buf_size)
+ return;
+
+ record.mnt_unique_id = p->mnt_unique_id;
+ record.mnt_id = p->mnt_id;
+ record.parent_id = is_root ? p->mnt_id : p->mnt_parent->mnt_id;
+ memcpy(ctx->buffer + usage, &record, sizeof(record));
+}
+
+/*
+ * Return information about the submounts relative to path.
+ */
+int fsinfo_generic_mount_children(struct path *path, struct fsinfo_context *ctx)
+{
+ struct mount *m, *child;
+
+ m = real_mount(path->mnt);
+
+ read_seqlock_excl(&mount_lock);
+
+ list_for_each_entry_rcu(child, &m->mnt_mounts, mnt_child) {
+ if (child->mnt_parent != m)
+ continue;
+ fsinfo_store_mount(ctx, child, false);
+ }
+
+ /* End the list with a copy of the parameter mount's details so that
+ * userspace can quickly check for changes.
+ */
+ fsinfo_store_mount(ctx, m, true);
+ read_sequnlock_excl(&mount_lock);
+ return ctx->usage;
+}
+
#endif /* CONFIG_FSINFO */
diff --git a/include/uapi/linux/fsinfo.h b/include/uapi/linux/fsinfo.h
index 15ef161905cd..f0a352b7028e 100644
--- a/include/uapi/linux/fsinfo.h
+++ b/include/uapi/linux/fsinfo.h
@@ -35,6 +35,8 @@
#define FSINFO_ATTR_MOUNT_PATH 0x201 /* Bind mount/superblock path (string) */
#define FSINFO_ATTR_MOUNT_POINT 0x202 /* Relative path of mount in parent (string) */
#define FSINFO_ATTR_MOUNT_POINT_FULL 0x203 /* Absolute path of mount (string) */
+#define FSINFO_ATTR_MOUNT_TOPOLOGY 0x204 /* Mount object topology */
+#define FSINFO_ATTR_MOUNT_CHILDREN 0x205 /* Children of this mount (list) */
/*
* Optional fsinfo() parameter structure.
@@ -102,6 +104,31 @@ struct fsinfo_mount_info {
#define FSINFO_ATTR_MOUNT_INFO__STRUCT struct fsinfo_mount_info
+/*
+ * Information struct for fsinfo(FSINFO_ATTR_MOUNT_TOPOLOGY).
+ */
+struct fsinfo_mount_topology {
+ __u32 parent_id; /* Parent mount identifier */
+ __u32 shared_group_id; /* Shared: mount group ID */
+ __u32 dependent_source_id; /* Dependent: source mount group ID */
+ __u32 dependent_clone_of_id; /* Dependent: ID of mount this was cloned from */
+ __u32 propagation_type; /* MOUNT_PROPAGATION_* type */
+};
+
+#define FSINFO_ATTR_MOUNT_TOPOLOGY__STRUCT struct fsinfo_mount_topology
+
+/*
+ * Information struct element for fsinfo(FSINFO_ATTR_MOUNT_CHILDREN).
+ * - An extra element is placed on the end representing the parent mount.
+ */
+struct fsinfo_mount_child {
+ __u64 mnt_unique_id; /* Kernel-lifetime unique mount ID */
+ __u32 mnt_id; /* Mount identifier (use with AT_FSINFO_MOUNTID_PATH) */
+ __u32 parent_id; /* Parent mount identifier */
+};
+
+#define FSINFO_ATTR_MOUNT_CHILDREN__STRUCT struct fsinfo_mount_child
+
/*
* Information struct for fsinfo(FSINFO_ATTR_STATFS).
* - This gives extended filesystem information.
diff --git a/include/uapi/linux/mount.h b/include/uapi/linux/mount.h
index 96a0240f23fe..9ac8bb708843 100644
--- a/include/uapi/linux/mount.h
+++ b/include/uapi/linux/mount.h
@@ -105,7 +105,7 @@ enum fsconfig_command {
#define FSMOUNT_CLOEXEC 0x00000001
/*
- * Mount attributes.
+ * Mount object attributes (these are separate to filesystem attributes).
*/
#define MOUNT_ATTR_RDONLY 0x00000001 /* Mount read-only */
#define MOUNT_ATTR_NOSUID 0x00000002 /* Ignore suid and sgid bits */
@@ -117,4 +117,15 @@ enum fsconfig_command {
#define MOUNT_ATTR_STRICTATIME 0x00000020 /* - Always perform atime updates */
#define MOUNT_ATTR_NODIRATIME 0x00000080 /* Do not update directory access times */
+/*
+ * Mount object propagation type.
+ */
+enum propagation_type {
+ /* 0 is left unallocated to mean "no change" in mount_setattr() */
+ MOUNT_PROPAGATION_UNBINDABLE = 1, /* Make unbindable. */
+ MOUNT_PROPAGATION_PRIVATE = 2, /* Do not receive or send mount events. */
+ MOUNT_PROPAGATION_DEPENDENT = 3, /* Only receive mount events. */
+ MOUNT_PROPAGATION_SHARED = 4, /* Send and receive mount events. */
+};
+
#endif /* _UAPI_LINUX_MOUNT_H */
diff --git a/samples/vfs/test-fsinfo.c b/samples/vfs/test-fsinfo.c
index f3bebb7318d9..b7290ea8eb55 100644
--- a/samples/vfs/test-fsinfo.c
+++ b/samples/vfs/test-fsinfo.c
@@ -21,6 +21,7 @@
#include <sys/syscall.h>
#include <linux/fsinfo.h>
#include <linux/socket.h>
+#include <linux/mount.h>
#include <sys/stat.h>
#include <arpa/inet.h>
@@ -305,6 +306,58 @@ static void dump_fsinfo_generic_mount_info(void *reply, unsigned int size)
printf("\tattr : %x\n", r->attr);
}
+static void dump_fsinfo_generic_mount_topology(void *reply, unsigned int size)
+{
+ struct fsinfo_mount_topology *r = reply;
+
+ printf("\n");
+ printf("\tparent : %x\n", r->parent_id);
+
+ switch (r->propagation_type) {
+ case MOUNT_PROPAGATION_UNBINDABLE:
+ printf("\tpropag : unbindable\n");
+ break;
+ case MOUNT_PROPAGATION_PRIVATE:
+ printf("\tpropag : private\n");
+ break;
+ case MOUNT_PROPAGATION_DEPENDENT:
+ printf("\tpropag : dependent source=%x clone_of=%x\n",
+ r->dependent_source_id, r->dependent_clone_of_id);
+ break;
+ case MOUNT_PROPAGATION_SHARED:
+ printf("\tpropag : shared group=%x\n", r->shared_group_id);
+ break;
+ default:
+ printf("\tpropag : unknown type %x\n", r->propagation_type);
+ break;
+ }
+
+}
+
+static void dump_fsinfo_generic_mount_children(void *reply, unsigned int size)
+{
+ struct fsinfo_mount_child *r = reply;
+ ssize_t mplen;
+ char path[32], *mp;
+
+ struct fsinfo_params params = {
+ .flags = FSINFO_FLAGS_QUERY_MOUNT,
+ .request = FSINFO_ATTR_MOUNT_POINT,
+ };
+
+ if (!list_last) {
+ sprintf(path, "%u", r->mnt_id);
+ mplen = get_fsinfo(path, "FSINFO_ATTR_MOUNT_POINT", ¶ms, (void **)&mp);
+ if (mplen < 0)
+ mp = "-";
+ } else {
+ mp = "<this>";
+ }
+
+ printf("%8x %16llx %s\n",
+ r->mnt_id, (unsigned long long)r->mnt_unique_id, mp);
+}
+
static void dump_string(void *reply, unsigned int size)
{
char *s = reply, *p;
@@ -383,9 +436,11 @@ static const struct fsinfo_attribute fsinfo_attributes[] = {
FSINFO_LIST (FSINFO_ATTR_FSINFO_ATTRIBUTES, fsinfo_meta_attributes),
FSINFO_VSTRUCT (FSINFO_ATTR_MOUNT_INFO, fsinfo_generic_mount_info),
+ FSINFO_VSTRUCT (FSINFO_ATTR_MOUNT_TOPOLOGY, fsinfo_generic_mount_topology),
FSINFO_STRING (FSINFO_ATTR_MOUNT_PATH, string),
FSINFO_STRING_N (FSINFO_ATTR_MOUNT_POINT, string),
FSINFO_STRING_N (FSINFO_ATTR_MOUNT_POINT_FULL, string),
+ FSINFO_LIST (FSINFO_ATTR_MOUNT_CHILDREN, fsinfo_generic_mount_children),
{}
};
^ permalink raw reply related
* [PATCH 07/18] fsinfo: Allow mount information to be queried [ver #21]
From: David Howells @ 2020-08-03 13:37 UTC (permalink / raw)
To: viro
Cc: dhowells, torvalds, raven, mszeredi, christian, jannh,
darrick.wong, kzak, jlayton, linux-api, linux-fsdevel,
linux-security-module, linux-kernel
In-Reply-To: <159646178122.1784947.11705396571718464082.stgit@warthog.procyon.org.uk>
Allow mount information, including information about a mount object to be
queried with the fsinfo() system call. Setting FSINFO_FLAGS_QUERY_MOUNT
allows overlapping mounts to be queried by indicating that the syscall
should interpret the pathname as a number indicating the mount ID.
To this end, a number of fsinfo() attributes are provided:
(1) FSINFO_ATTR_MOUNT_INFO.
This is a structure providing information about a mount, including:
- Mount ID (can be used with FSINFO_FLAGS_QUERY_MOUNT).
- Mount uniquifier ID.
- Mount attributes (eg. R/O, NOEXEC).
- Mount change/notification counters.
- Superblock ID.
- Superblock change/notification counters.
(2) FSINFO_ATTR_MOUNT_PATH.
This a string providing information about a bind mount relative the
the root that was bound off, though it may get overridden by the
filesystem (NFS unconditionally sets it to "/", for example).
(3) FSINFO_ATTR_MOUNT_POINT.
This is a string indicating the name of the mountpoint within the
parent mount, limited to the parent's mounted root and the chroot.
(4) FSINFO_ATTR_MOUNT_POINT_FULL.
This is a string indicating the full path of the mountpoint, limited to
the chroot.
Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/d_path.c | 2 -
fs/fsinfo.c | 12 +++++
fs/internal.h | 9 +++
fs/namespace.c | 114 +++++++++++++++++++++++++++++++++++++++++++
include/uapi/linux/fsinfo.h | 17 ++++++
samples/vfs/test-fsinfo.c | 16 ++++++
6 files changed, 169 insertions(+), 1 deletion(-)
diff --git a/fs/d_path.c b/fs/d_path.c
index 0f1fc1743302..4c203f64e45e 100644
--- a/fs/d_path.c
+++ b/fs/d_path.c
@@ -229,7 +229,7 @@ static int prepend_unreachable(char **buffer, int *buflen)
return prepend(buffer, buflen, "(unreachable)", 13);
}
-static void get_fs_root_rcu(struct fs_struct *fs, struct path *root)
+void get_fs_root_rcu(struct fs_struct *fs, struct path *root)
{
unsigned seq;
diff --git a/fs/fsinfo.c b/fs/fsinfo.c
index 8ccbcddb4f16..f276857709ee 100644
--- a/fs/fsinfo.c
+++ b/fs/fsinfo.c
@@ -252,6 +252,13 @@ static int fsinfo_generic_seq_read(struct path *path, struct fsinfo_context *ctx
ret = sb->s_op->show_options(&m, path->mnt->mnt_root);
break;
+ case FSINFO_ATTR_MOUNT_PATH:
+ if (sb->s_op->show_path)
+ ret = sb->s_op->show_path(&m, path->mnt->mnt_root);
+ else
+ seq_dentry(&m, path->mnt->mnt_root, " \t\n\\");
+ break;
+
case FSINFO_ATTR_FS_STATISTICS:
if (sb->s_op->show_stats)
ret = sb->s_op->show_stats(&m, path->mnt->mnt_root);
@@ -282,6 +289,11 @@ static const struct fsinfo_attribute fsinfo_common_attributes[] = {
FSINFO_LIST (FSINFO_ATTR_FSINFO_ATTRIBUTES, (void *)123UL),
FSINFO_VSTRUCT_N(FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO, (void *)123UL),
+
+ FSINFO_VSTRUCT (FSINFO_ATTR_MOUNT_INFO, fsinfo_generic_mount_info),
+ FSINFO_STRING (FSINFO_ATTR_MOUNT_PATH, fsinfo_generic_seq_read),
+ FSINFO_STRING (FSINFO_ATTR_MOUNT_POINT, fsinfo_generic_mount_point),
+ FSINFO_STRING (FSINFO_ATTR_MOUNT_POINT_FULL, fsinfo_generic_mount_point_full),
{}
};
diff --git a/fs/internal.h b/fs/internal.h
index 84bbb743a5ac..a56008b7f3ec 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -15,6 +15,7 @@ struct mount;
struct shrink_control;
struct fs_context;
struct user_namespace;
+struct fsinfo_context;
/*
* block_dev.c
@@ -46,6 +47,11 @@ extern int __block_write_begin_int(struct page *page, loff_t pos, unsigned len,
*/
extern void __init chrdev_init(void);
+/*
+ * d_path.c
+ */
+extern void get_fs_root_rcu(struct fs_struct *fs, struct path *root);
+
/*
* fs_context.c
*/
@@ -91,6 +97,9 @@ extern void __mnt_drop_write_file(struct file *);
extern void dissolve_on_fput(struct vfsmount *);
extern int lookup_mount_object(struct path *, unsigned int, struct path *);
extern int fsinfo_generic_mount_source(struct path *, struct fsinfo_context *);
+extern int fsinfo_generic_mount_info(struct path *, struct fsinfo_context *);
+extern int fsinfo_generic_mount_point(struct path *, struct fsinfo_context *);
+extern int fsinfo_generic_mount_point_full(struct path *, struct fsinfo_context *);
/*
* fs_struct.c
diff --git a/fs/namespace.c b/fs/namespace.c
index 1db8a64cd76f..c196af35d39d 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -4265,4 +4265,118 @@ int lookup_mount_object(struct path *root, unsigned int mnt_id, struct path *_mn
goto out_unlock;
}
+/*
+ * Retrieve information about the nominated mount.
+ */
+int fsinfo_generic_mount_info(struct path *path, struct fsinfo_context *ctx)
+{
+ struct fsinfo_mount_info *p = ctx->buffer;
+ struct super_block *sb;
+ struct mount *m;
+ unsigned int flags;
+
+ m = real_mount(path->mnt);
+ sb = m->mnt.mnt_sb;
+
+ p->sb_unique_id = sb->s_unique_id;
+ p->mnt_unique_id = m->mnt_unique_id;
+ p->mnt_id = m->mnt_id;
+
+ flags = READ_ONCE(m->mnt.mnt_flags);
+ if (flags & MNT_READONLY)
+ p->attr |= MOUNT_ATTR_RDONLY;
+ if (flags & MNT_NOSUID)
+ p->attr |= MOUNT_ATTR_NOSUID;
+ if (flags & MNT_NODEV)
+ p->attr |= MOUNT_ATTR_NODEV;
+ if (flags & MNT_NOEXEC)
+ p->attr |= MOUNT_ATTR_NOEXEC;
+ if (flags & MNT_NODIRATIME)
+ p->attr |= MOUNT_ATTR_NODIRATIME;
+
+ if (flags & MNT_NOATIME)
+ p->attr |= MOUNT_ATTR_NOATIME;
+ else if (flags & MNT_RELATIME)
+ p->attr |= MOUNT_ATTR_RELATIME;
+ else
+ p->attr |= MOUNT_ATTR_STRICTATIME;
+ return sizeof(*p);
+}
+
+/*
+ * Return the path of this mount relative to its parent and clipped to
+ * the current chroot.
+ */
+int fsinfo_generic_mount_point(struct path *path, struct fsinfo_context *ctx)
+{
+ struct mountpoint *mp;
+ struct mount *m, *parent;
+ struct path mountpoint, root;
+ void *p;
+
+ rcu_read_lock();
+
+ m = real_mount(path->mnt);
+ parent = m->mnt_parent;
+ if (parent == m)
+ goto skip;
+ mp = READ_ONCE(m->mnt_mp);
+ if (mp)
+ goto found;
+skip:
+ rcu_read_unlock();
+ return -ENODATA;
+
+found:
+ mountpoint.mnt = &parent->mnt;
+ mountpoint.dentry = READ_ONCE(mp->m_dentry);
+
+ get_fs_root_rcu(current->fs, &root);
+ if (path->mnt == root.mnt) {
+ rcu_read_unlock();
+ return fsinfo_string("/", ctx);
+ }
+
+ if (root.mnt != &parent->mnt) {
+ root.mnt = &parent->mnt;
+ root.dentry = parent->mnt.mnt_root;
+ }
+
+ ((char *)ctx->buffer)[ctx->buf_size - 1] = 0;
+ p = __d_path(&mountpoint, &root, ctx->buffer, ctx->buf_size - 1);
+ rcu_read_unlock();
+
+ if (IS_ERR(p))
+ return PTR_ERR(p);
+ if (!p)
+ return -EPERM;
+
+ ctx->skip = p - ctx->buffer;
+ return (ctx->buffer + ctx->buf_size) - p;
+}
+
+/*
+ * Return the path of this mount from the current chroot.
+ */
+int fsinfo_generic_mount_point_full(struct path *path, struct fsinfo_context *ctx)
+{
+ struct path root;
+ void *p;
+
+ ((char *)ctx->buffer)[ctx->buf_size - 1] = 0;
+
+ rcu_read_lock();
+ get_fs_root_rcu(current->fs, &root);
+ p = __d_path(path, &root, ctx->buffer, ctx->buf_size - 1);
+ rcu_read_unlock();
+
+ if (IS_ERR(p))
+ return PTR_ERR(p);
+ if (!p)
+ return -EPERM;
+
+ ctx->skip = p - ctx->buffer;
+ return (ctx->buffer + ctx->buf_size) - p;
+}
+
#endif /* CONFIG_FSINFO */
diff --git a/include/uapi/linux/fsinfo.h b/include/uapi/linux/fsinfo.h
index d24e47762a07..15ef161905cd 100644
--- a/include/uapi/linux/fsinfo.h
+++ b/include/uapi/linux/fsinfo.h
@@ -31,6 +31,11 @@
#define FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO 0x100 /* Information about attr N (for path) */
#define FSINFO_ATTR_FSINFO_ATTRIBUTES 0x101 /* List of supported attrs (for path) */
+#define FSINFO_ATTR_MOUNT_INFO 0x200 /* Mount object information */
+#define FSINFO_ATTR_MOUNT_PATH 0x201 /* Bind mount/superblock path (string) */
+#define FSINFO_ATTR_MOUNT_POINT 0x202 /* Relative path of mount in parent (string) */
+#define FSINFO_ATTR_MOUNT_POINT_FULL 0x203 /* Absolute path of mount (string) */
+
/*
* Optional fsinfo() parameter structure.
*
@@ -85,6 +90,18 @@ struct fsinfo_u128 {
#endif
};
+/*
+ * Information struct for fsinfo(FSINFO_ATTR_MOUNT_INFO).
+ */
+struct fsinfo_mount_info {
+ __u64 sb_unique_id; /* Kernel-lifetime unique superblock ID */
+ __u64 mnt_unique_id; /* Kernel-lifetime unique mount ID */
+ __u32 mnt_id; /* Mount identifier (use with AT_FSINFO_MOUNTID_PATH) */
+ __u32 attr; /* MOUNT_ATTR_* flags */
+};
+
+#define FSINFO_ATTR_MOUNT_INFO__STRUCT struct fsinfo_mount_info
+
/*
* Information struct for fsinfo(FSINFO_ATTR_STATFS).
* - This gives extended filesystem information.
diff --git a/samples/vfs/test-fsinfo.c b/samples/vfs/test-fsinfo.c
index dfa44bba8bbd..f3bebb7318d9 100644
--- a/samples/vfs/test-fsinfo.c
+++ b/samples/vfs/test-fsinfo.c
@@ -294,6 +294,17 @@ static void dump_fsinfo_generic_volume_uuid(void *reply, unsigned int size)
f->uuid[14], f->uuid[15]);
}
+static void dump_fsinfo_generic_mount_info(void *reply, unsigned int size)
+{
+ struct fsinfo_mount_info *r = reply;
+
+ printf("\n");
+ printf("\tsb_uniq : %llx\n", (unsigned long long)r->sb_unique_id);
+ printf("\tmnt_uniq: %llx\n", (unsigned long long)r->mnt_unique_id);
+ printf("\tmnt_id : %x\n", r->mnt_id);
+ printf("\tattr : %x\n", r->attr);
+}
+
static void dump_string(void *reply, unsigned int size)
{
char *s = reply, *p;
@@ -370,6 +381,11 @@ static const struct fsinfo_attribute fsinfo_attributes[] = {
FSINFO_VSTRUCT_N(FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO, fsinfo_meta_attribute_info),
FSINFO_LIST (FSINFO_ATTR_FSINFO_ATTRIBUTES, fsinfo_meta_attributes),
+
+ FSINFO_VSTRUCT (FSINFO_ATTR_MOUNT_INFO, fsinfo_generic_mount_info),
+ FSINFO_STRING (FSINFO_ATTR_MOUNT_PATH, string),
+ FSINFO_STRING_N (FSINFO_ATTR_MOUNT_POINT, string),
+ FSINFO_STRING_N (FSINFO_ATTR_MOUNT_POINT_FULL, string),
{}
};
^ permalink raw reply related
* [PATCH 06/18] fsinfo: Add a uniquifier ID to struct mount [ver #21]
From: David Howells @ 2020-08-03 13:37 UTC (permalink / raw)
To: viro
Cc: dhowells, torvalds, raven, mszeredi, christian, jannh,
darrick.wong, kzak, jlayton, linux-api, linux-fsdevel,
linux-security-module, linux-kernel
In-Reply-To: <159646178122.1784947.11705396571718464082.stgit@warthog.procyon.org.uk>
Add a uniquifier ID to struct mount that is effectively unique over the
kernel lifetime to deal around mnt_id values being reused. This can then
be exported through fsinfo() to allow detection of replacement mounts that
happen to end up with the same mount ID.
The normal mount handle is still used for referring to a particular mount.
The mount notification is then changed to convey these unique mount IDs
rather than the mount handle.
Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/mount.h | 3 +++
fs/mount_notify.c | 4 ++--
fs/namespace.c | 3 +++
3 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/fs/mount.h b/fs/mount.h
index 85456a5f5a3a..1037781be055 100644
--- a/fs/mount.h
+++ b/fs/mount.h
@@ -79,6 +79,9 @@ struct mount {
int mnt_expiry_mark; /* true if marked for expiry */
struct hlist_head mnt_pins;
struct hlist_head mnt_stuck_children;
+#ifdef CONFIG_FSINFO
+ u64 mnt_unique_id; /* ID unique over lifetime of kernel */
+#endif
#ifdef CONFIG_MOUNT_NOTIFICATIONS
struct watch_list *mnt_watchers; /* Watches on dentries within this mount */
#endif
diff --git a/fs/mount_notify.c b/fs/mount_notify.c
index 44f570e4cebe..d8ba66ed5f77 100644
--- a/fs/mount_notify.c
+++ b/fs/mount_notify.c
@@ -90,7 +90,7 @@ void notify_mount(struct mount *trigger,
n.watch.type = WATCH_TYPE_MOUNT_NOTIFY;
n.watch.subtype = subtype;
n.watch.info = info_flags | watch_sizeof(n);
- n.triggered_on = trigger->mnt_id;
+ n.triggered_on = trigger->mnt_unique_id;
switch (subtype) {
case NOTIFY_MOUNT_EXPIRY:
@@ -102,7 +102,7 @@ void notify_mount(struct mount *trigger,
case NOTIFY_MOUNT_UNMOUNT:
case NOTIFY_MOUNT_MOVE_FROM:
case NOTIFY_MOUNT_MOVE_TO:
- n.auxiliary_mount = aux->mnt_id;
+ n.auxiliary_mount = aux->mnt_unique_id;
break;
default:
diff --git a/fs/namespace.c b/fs/namespace.c
index b2b9920ffd3c..1db8a64cd76f 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -115,6 +115,9 @@ static int mnt_alloc_id(struct mount *mnt)
if (res < 0)
return res;
mnt->mnt_id = res;
+#ifdef CONFIG_FSINFO
+ mnt->mnt_unique_id = atomic64_inc_return(&vfs_unique_counter);
+#endif
return 0;
}
^ permalink raw reply related
* [PATCH 05/18] fsinfo: Allow fsinfo() to look up a mount object by ID [ver #21]
From: David Howells @ 2020-08-03 13:37 UTC (permalink / raw)
To: viro
Cc: dhowells, torvalds, raven, mszeredi, christian, jannh,
darrick.wong, kzak, jlayton, linux-api, linux-fsdevel,
linux-security-module, linux-kernel
In-Reply-To: <159646178122.1784947.11705396571718464082.stgit@warthog.procyon.org.uk>
Allow the fsinfo() syscall to look up a mount object by ID rather than by
pathname. This is necessary as there can be multiple mounts stacked up at
the same pathname and there's no way to look through them otherwise.
This is done by passing FSINFO_FLAGS_QUERY_MOUNT to fsinfo() in the
parameters and then passing the mount ID as a string to fsinfo() in place
of the filename:
struct fsinfo_params params = {
.flags = FSINFO_FLAGS_QUERY_MOUNT,
.request = FSINFO_ATTR_IDS,
};
ret = fsinfo(AT_FDCWD, "21", ¶ms, buffer, sizeof(buffer));
The caller is only permitted to query a mount object if the root directory
of that mount connects directly to the current chroot if dfd == AT_FDCWD[*]
or the directory specified by dfd otherwise. Note that this is not
available to the pathwalk of any other syscall.
[*] This needs to be something other than AT_FDCWD, perhaps AT_FDROOT.
[!] This probably needs an LSM hook.
[!] This might want to check the permissions on all the intervening dirs -
but it would have to do that under RCU conditions.
[!] This might want to check a CAP_* flag.
Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/fsinfo.c | 53 +++++++++++++++++++
fs/internal.h | 1
fs/namespace.c | 117 ++++++++++++++++++++++++++++++++++++++++++-
include/uapi/linux/fsinfo.h | 1
samples/vfs/test-fsinfo.c | 7 ++-
5 files changed, 175 insertions(+), 4 deletions(-)
diff --git a/fs/fsinfo.c b/fs/fsinfo.c
index aef7a736e8fc..8ccbcddb4f16 100644
--- a/fs/fsinfo.c
+++ b/fs/fsinfo.c
@@ -563,6 +563,56 @@ static int vfs_fsinfo_fd(unsigned int fd, struct fsinfo_context *ctx)
return ret;
}
+/*
+ * Look up the root of a mount object. This allows access to mount objects
+ * (and their attached superblocks) that can't be retrieved by path because
+ * they're entirely covered.
+ *
+ * We only permit access to a mount that has a direct path between either the
+ * dentry pointed to by dfd or to our chroot (if dfd is AT_FDCWD).
+ */
+static int vfs_fsinfo_mount(int dfd, const char __user *filename,
+ struct fsinfo_context *ctx)
+{
+ struct path path;
+ struct fd f = {};
+ char *name;
+ unsigned long mnt_id;
+ int ret;
+
+ if (!filename)
+ return -EINVAL;
+
+ name = strndup_user(filename, 32);
+ if (IS_ERR(name))
+ return PTR_ERR(name);
+ ret = kstrtoul(name, 0, &mnt_id);
+ if (ret < 0)
+ goto out_name;
+ if (mnt_id > INT_MAX)
+ goto out_name;
+
+ if (dfd != AT_FDCWD) {
+ ret = -EBADF;
+ f = fdget_raw(dfd);
+ if (!f.file)
+ goto out_name;
+ }
+
+ ret = lookup_mount_object(f.file ? &f.file->f_path : NULL,
+ mnt_id, &path);
+ if (ret < 0)
+ goto out_fd;
+
+ ret = vfs_fsinfo(&path, ctx);
+ path_put(&path);
+out_fd:
+ fdput(f);
+out_name:
+ kfree(name);
+ return ret;
+}
+
/**
* sys_fsinfo - System call to get filesystem information
* @dfd: Base directory to pathwalk from or fd referring to filesystem.
@@ -636,6 +686,9 @@ SYSCALL_DEFINE6(fsinfo,
return -EINVAL;
ret = vfs_fsinfo_fd(dfd, &ctx);
break;
+ case FSINFO_FLAGS_QUERY_MOUNT:
+ ret = vfs_fsinfo_mount(dfd, pathname, &ctx);
+ break;
default:
return -EINVAL;
}
diff --git a/fs/internal.h b/fs/internal.h
index 0b57da498f06..84bbb743a5ac 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -89,6 +89,7 @@ extern int __mnt_want_write_file(struct file *);
extern void __mnt_drop_write_file(struct file *);
extern void dissolve_on_fput(struct vfsmount *);
+extern int lookup_mount_object(struct path *, unsigned int, struct path *);
extern int fsinfo_generic_mount_source(struct path *, struct fsinfo_context *);
/*
diff --git a/fs/namespace.c b/fs/namespace.c
index ead8d1a16610..b2b9920ffd3c 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -64,7 +64,7 @@ static int __init set_mphash_entries(char *str)
__setup("mphash_entries=", set_mphash_entries);
static u64 event;
-static DEFINE_IDA(mnt_id_ida);
+static DEFINE_IDR(mnt_id_ida);
static DEFINE_IDA(mnt_group_ida);
static struct hlist_head *mount_hashtable __read_mostly;
@@ -105,17 +105,27 @@ static inline struct hlist_head *mp_hash(struct dentry *dentry)
static int mnt_alloc_id(struct mount *mnt)
{
- int res = ida_alloc(&mnt_id_ida, GFP_KERNEL);
+ int res;
+ /* Allocate an ID, but don't set the pointer back to the mount until
+ * later, as once we do that, we have to follow RCU protocols to get
+ * rid of the mount struct.
+ */
+ res = idr_alloc(&mnt_id_ida, NULL, 0, INT_MAX, GFP_KERNEL);
if (res < 0)
return res;
mnt->mnt_id = res;
return 0;
}
+static void mnt_publish_id(struct mount *mnt)
+{
+ idr_replace(&mnt_id_ida, mnt, mnt->mnt_id);
+}
+
static void mnt_free_id(struct mount *mnt)
{
- ida_free(&mnt_id_ida, mnt->mnt_id);
+ idr_remove(&mnt_id_ida, mnt->mnt_id);
}
/*
@@ -975,6 +985,7 @@ struct vfsmount *vfs_create_mount(struct fs_context *fc)
lock_mount_hash();
list_add_tail(&mnt->mnt_instance, &mnt->mnt.mnt_sb->s_mounts);
unlock_mount_hash();
+ mnt_publish_id(mnt);
return &mnt->mnt;
}
EXPORT_SYMBOL(vfs_create_mount);
@@ -1068,6 +1079,7 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root,
lock_mount_hash();
list_add_tail(&mnt->mnt_instance, &sb->s_mounts);
unlock_mount_hash();
+ mnt_publish_id(mnt);
if ((flag & CL_SLAVE) ||
((flag & CL_SHARED_TO_SLAVE) && IS_MNT_SHARED(old))) {
@@ -4151,4 +4163,103 @@ int fsinfo_generic_mount_source(struct path *path, struct fsinfo_context *ctx)
return m.count + 1;
}
+/*
+ * See if one path point connects directly to another by ancestral relationship
+ * across mountpoints. Must call with the RCU read lock held.
+ */
+static bool are_paths_connected(struct path *ancestor, struct path *to_check)
+{
+ struct mount *mnt, *parent;
+ struct path cursor;
+ unsigned seq;
+ bool connected;
+
+ seq = 0;
+restart:
+ cursor = *to_check;
+
+ read_seqbegin_or_lock(&rename_lock, &seq);
+ while (cursor.mnt != ancestor->mnt) {
+ mnt = real_mount(cursor.mnt);
+ parent = READ_ONCE(mnt->mnt_parent);
+ if (mnt == parent)
+ goto failed;
+ cursor.dentry = READ_ONCE(mnt->mnt_mountpoint);
+ cursor.mnt = &parent->mnt;
+ }
+
+ while (cursor.dentry != ancestor->dentry) {
+ if (cursor.dentry == cursor.mnt->mnt_root ||
+ IS_ROOT(cursor.dentry))
+ goto failed;
+ cursor.dentry = READ_ONCE(cursor.dentry->d_parent);
+ }
+
+ connected = true;
+out:
+ done_seqretry(&rename_lock, seq);
+ return connected;
+
+failed:
+ if (need_seqretry(&rename_lock, seq)) {
+ seq = 1;
+ goto restart;
+ }
+ connected = false;
+ goto out;
+}
+
+/**
+ * lookup_mount_object - Look up a vfsmount object by ID
+ * @root: The mount root must connect backwards to this point (or chroot if NULL).
+ * @id: The ID of the mountpoint.
+ * @_mntpt: Where to return the resulting mountpoint path.
+ *
+ * Look up the root of the mount with the corresponding ID. This is only
+ * permitted if that mount connects directly to the specified root/chroot.
+ */
+int lookup_mount_object(struct path *root, unsigned int mnt_id, struct path *_mntpt)
+{
+ struct mount *mnt;
+ struct path stop, mntpt = {};
+ int ret = -EPERM;
+
+ if (!root)
+ get_fs_root(current->fs, &stop);
+ else
+ stop = *root;
+
+ rcu_read_lock();
+ lock_mount_hash();
+ mnt = idr_find(&mnt_id_ida, mnt_id);
+ if (!mnt)
+ goto out_unlock_mh;
+ if (mnt->mnt.mnt_flags & (MNT_SYNC_UMOUNT | MNT_UMOUNT | MNT_DOOMED))
+ goto out_unlock_mh;
+ if (mnt_get_count(mnt) == 0)
+ goto out_unlock_mh;
+ mnt_add_count(mnt, 1);
+ mntpt.mnt = &mnt->mnt;
+ mntpt.dentry = dget(mnt->mnt.mnt_root);
+ unlock_mount_hash();
+
+ if (are_paths_connected(&stop, &mntpt)) {
+ *_mntpt = mntpt;
+ mntpt.mnt = NULL;
+ mntpt.dentry = NULL;
+ ret = 0;
+ }
+
+out_unlock:
+ rcu_read_unlock();
+ if (!root)
+ path_put(&stop);
+ path_put(&mntpt);
+ return ret;
+
+out_unlock_mh:
+ unlock_mount_hash();
+ goto out_unlock;
+}
+
#endif /* CONFIG_FSINFO */
diff --git a/include/uapi/linux/fsinfo.h b/include/uapi/linux/fsinfo.h
index a27e92b68266..d24e47762a07 100644
--- a/include/uapi/linux/fsinfo.h
+++ b/include/uapi/linux/fsinfo.h
@@ -44,6 +44,7 @@ struct fsinfo_params {
#define FSINFO_FLAGS_QUERY_MASK 0x0007 /* What object should fsinfo() query? */
#define FSINFO_FLAGS_QUERY_PATH 0x0000 /* - path, specified by dirfd,pathname,AT_EMPTY_PATH */
#define FSINFO_FLAGS_QUERY_FD 0x0001 /* - fd specified by dirfd */
+#define FSINFO_FLAGS_QUERY_MOUNT 0x0002 /* - mount object (path=>mount_id, dirfd=>subtree) */
__u32 request; /* ID of requested attribute */
__u32 Nth; /* Instance of it (some may have multiple) */
__u32 Mth; /* Subinstance of Nth instance */
diff --git a/samples/vfs/test-fsinfo.c b/samples/vfs/test-fsinfo.c
index 634f30b7e67f..dfa44bba8bbd 100644
--- a/samples/vfs/test-fsinfo.c
+++ b/samples/vfs/test-fsinfo.c
@@ -593,7 +593,7 @@ int main(int argc, char **argv)
bool meta = false;
int raw = 0, opt, Nth, Mth;
- while ((opt = getopt(argc, argv, "Madlr"))) {
+ while ((opt = getopt(argc, argv, "Madmlr"))) {
switch (opt) {
case 'M':
meta = true;
@@ -609,6 +609,10 @@ int main(int argc, char **argv)
params.at_flags &= ~AT_SYMLINK_NOFOLLOW;
params.flags = FSINFO_FLAGS_QUERY_PATH;
continue;
+ case 'm':
+ params.resolve_flags = 0;
+ params.flags = FSINFO_FLAGS_QUERY_MOUNT;
+ continue;
case 'r':
raw = 1;
continue;
@@ -621,6 +625,7 @@ int main(int argc, char **argv)
if (argc != 1) {
printf("Format: test-fsinfo [-Madlr] <path>\n");
+ printf("Format: test-fsinfo [-Mdr] -m <mnt_id>\n");
exit(2);
}
^ permalink raw reply related
* [PATCH 04/18] fsinfo: Allow retrieval of superblock devname, options and stats [ver #21]
From: David Howells @ 2020-08-03 13:37 UTC (permalink / raw)
To: viro
Cc: dhowells, torvalds, raven, mszeredi, christian, jannh,
darrick.wong, kzak, jlayton, linux-api, linux-fsdevel,
linux-security-module, linux-kernel
In-Reply-To: <159646178122.1784947.11705396571718464082.stgit@warthog.procyon.org.uk>
Provide fsinfo() attributes to retrieve superblock device name, options,
and statistics in string form. The following attributes are defined:
FSINFO_ATTR_SOURCE - Mount-specific device name
FSINFO_ATTR_CONFIGURATION - Mount options
FSINFO_ATTR_FS_STATISTICS - Filesystem statistics
FSINFO_ATTR_SOURCE could be made indexable by params->Nth to handle the
case where there is more than one source (e.g. the bcachefs filesystem).
Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/fsinfo.c | 39 +++++++++++++++++++++++++++++++++++++++
fs/internal.h | 2 ++
fs/namespace.c | 41 +++++++++++++++++++++++++++++++++++++++++
include/uapi/linux/fsinfo.h | 3 +++
samples/vfs/test-fsinfo.c | 4 ++++
5 files changed, 89 insertions(+)
diff --git a/fs/fsinfo.c b/fs/fsinfo.c
index 79c222d465d8..aef7a736e8fc 100644
--- a/fs/fsinfo.c
+++ b/fs/fsinfo.c
@@ -231,6 +231,42 @@ static int fsinfo_generic_volume_id(struct path *path, struct fsinfo_context *ct
return fsinfo_string(path->dentry->d_sb->s_id, ctx);
}
+/*
+ * Retrieve the superblock configuration (mount options) as a comma-separated
+ * string. The initial comma is stripped off and NUL termination is added.
+ */
+static int fsinfo_generic_seq_read(struct path *path, struct fsinfo_context *ctx)
+{
+ struct super_block *sb = path->dentry->d_sb;
+ struct seq_file m = {
+ .buf = ctx->buffer,
+ .size = ctx->buf_size - 1,
+ };
+ int ret = 0;
+
+ switch (ctx->requested_attr) {
+ case FSINFO_ATTR_CONFIGURATION:
+ seq_puts(&m, sb_rdonly(sb) ? "ro" : "rw");
+ ret = security_sb_show_options(&m, sb);
+ if (!ret && sb->s_op->show_options)
+ ret = sb->s_op->show_options(&m, path->mnt->mnt_root);
+ break;
+
+ case FSINFO_ATTR_FS_STATISTICS:
+ if (sb->s_op->show_stats)
+ ret = sb->s_op->show_stats(&m, path->mnt->mnt_root);
+ break;
+ }
+
+ if (ret < 0)
+ return ret;
+ if (seq_has_overflowed(&m))
+ return ctx->buf_size + PAGE_SIZE;
+
+ ((char *)ctx->buffer)[ctx->skip + m.count] = 0;
+ return m.count + 1;
+}
+
static const struct fsinfo_attribute fsinfo_common_attributes[] = {
FSINFO_VSTRUCT (FSINFO_ATTR_STATFS, fsinfo_generic_statfs),
FSINFO_VSTRUCT (FSINFO_ATTR_IDS, fsinfo_generic_ids),
@@ -240,6 +276,9 @@ static const struct fsinfo_attribute fsinfo_common_attributes[] = {
FSINFO_STRING (FSINFO_ATTR_VOLUME_ID, fsinfo_generic_volume_id),
FSINFO_VSTRUCT (FSINFO_ATTR_VOLUME_UUID, fsinfo_generic_volume_uuid),
FSINFO_VSTRUCT (FSINFO_ATTR_FEATURES, fsinfo_generic_features),
+ FSINFO_STRING (FSINFO_ATTR_SOURCE, fsinfo_generic_mount_source),
+ FSINFO_STRING (FSINFO_ATTR_CONFIGURATION, fsinfo_generic_seq_read),
+ FSINFO_STRING (FSINFO_ATTR_FS_STATISTICS, fsinfo_generic_seq_read),
FSINFO_LIST (FSINFO_ATTR_FSINFO_ATTRIBUTES, (void *)123UL),
FSINFO_VSTRUCT_N(FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO, (void *)123UL),
diff --git a/fs/internal.h b/fs/internal.h
index ea60d864a8cb..0b57da498f06 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -89,6 +89,8 @@ extern int __mnt_want_write_file(struct file *);
extern void __mnt_drop_write_file(struct file *);
extern void dissolve_on_fput(struct vfsmount *);
+extern int fsinfo_generic_mount_source(struct path *, struct fsinfo_context *);
+
/*
* fs_struct.c
*/
diff --git a/fs/namespace.c b/fs/namespace.c
index 73ff5bf0c9af..ead8d1a16610 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -30,6 +30,7 @@
#include <uapi/linux/mount.h>
#include <linux/fs_context.h>
#include <linux/shmem_fs.h>
+#include <linux/fsinfo.h>
#include "pnode.h"
#include "internal.h"
@@ -4111,3 +4112,43 @@ const struct proc_ns_operations mntns_operations = {
.install = mntns_install,
.owner = mntns_owner,
};
+
+#ifdef CONFIG_FSINFO
+static inline void mangle(struct seq_file *m, const char *s)
+{
+ seq_escape(m, s, " \t\n\\");
+}
+
+/*
+ * Return the mount source/device name as seen from this mountpoint. Shared
+ * mounts may vary here and the filesystem is permitted to substitute its own
+ * rendering.
+ */
+int fsinfo_generic_mount_source(struct path *path, struct fsinfo_context *ctx)
+{
+ struct super_block *sb = path->mnt->mnt_sb;
+ struct mount *mnt = real_mount(path->mnt);
+ struct seq_file m = {
+ .buf = ctx->buffer,
+ .size = ctx->buf_size - 1,
+ };
+ int ret;
+
+ if (sb->s_op->show_devname) {
+ ret = sb->s_op->show_devname(&m, mnt->mnt.mnt_root);
+ if (ret < 0)
+ return ret;
+ } else {
+ if (!mnt->mnt_devname)
+ return fsinfo_string("none", ctx);
+ mangle(&m, mnt->mnt_devname);
+ }
+
+ if (seq_has_overflowed(&m))
+ return ctx->buf_size + PAGE_SIZE;
+
+ ((char *)ctx->buffer)[m.count] = 0;
+ return m.count + 1;
+}
+
+#endif /* CONFIG_FSINFO */
diff --git a/include/uapi/linux/fsinfo.h b/include/uapi/linux/fsinfo.h
index b8b2c836267b..a27e92b68266 100644
--- a/include/uapi/linux/fsinfo.h
+++ b/include/uapi/linux/fsinfo.h
@@ -24,6 +24,9 @@
#define FSINFO_ATTR_VOLUME_UUID 0x06 /* Volume UUID (LE uuid) */
#define FSINFO_ATTR_VOLUME_NAME 0x07 /* Volume name (string) */
#define FSINFO_ATTR_FEATURES 0x08 /* Filesystem features (bits) */
+#define FSINFO_ATTR_SOURCE 0x09 /* Superblock source/device name (string) */
+#define FSINFO_ATTR_CONFIGURATION 0x0a /* Superblock configuration/options (string) */
+#define FSINFO_ATTR_FS_STATISTICS 0x0b /* Superblock filesystem statistics (string) */
#define FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO 0x100 /* Information about attr N (for path) */
#define FSINFO_ATTR_FSINFO_ATTRIBUTES 0x101 /* List of supported attrs (for path) */
diff --git a/samples/vfs/test-fsinfo.c b/samples/vfs/test-fsinfo.c
index c5932109f683..634f30b7e67f 100644
--- a/samples/vfs/test-fsinfo.c
+++ b/samples/vfs/test-fsinfo.c
@@ -364,6 +364,10 @@ static const struct fsinfo_attribute fsinfo_attributes[] = {
FSINFO_STRING (FSINFO_ATTR_VOLUME_ID, string),
FSINFO_VSTRUCT (FSINFO_ATTR_VOLUME_UUID, fsinfo_generic_volume_uuid),
FSINFO_STRING (FSINFO_ATTR_VOLUME_NAME, string),
+ FSINFO_STRING (FSINFO_ATTR_SOURCE, string),
+ FSINFO_STRING (FSINFO_ATTR_CONFIGURATION, string),
+ FSINFO_STRING (FSINFO_ATTR_FS_STATISTICS, string),
+
FSINFO_VSTRUCT_N(FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO, fsinfo_meta_attribute_info),
FSINFO_LIST (FSINFO_ATTR_FSINFO_ATTRIBUTES, fsinfo_meta_attributes),
{}
^ permalink raw reply related
* [PATCH 03/18] fsinfo: Provide a bitmap of the features a filesystem supports [ver #21]
From: David Howells @ 2020-08-03 13:36 UTC (permalink / raw)
To: viro
Cc: dhowells, torvalds, raven, mszeredi, christian, jannh,
darrick.wong, kzak, jlayton, linux-api, linux-fsdevel,
linux-security-module, linux-kernel
In-Reply-To: <159646178122.1784947.11705396571718464082.stgit@warthog.procyon.org.uk>
Provide a bitmap of features that a filesystem may provide for the path
being queried. Features include such things as:
(1) The general class of filesystem, such as kernel-interface,
block-based, flash-based, network-based.
(2) Supported inode features, such as which timestamps are supported,
whether simple numeric user, group or project IDs are supported and
whether user identification is actually more complex behind the
scenes.
(3) Supported volume features, such as it having a UUID, a name or a
filesystem ID.
(4) Supported filesystem features, such as what types of file are
supported, whether sparse files, extended attributes and quotas are
supported.
(5) Supported interface features, such as whether locking and leases are
supported, what open flags are honoured and how i_version is managed.
For some filesystems, this may be an immutable set and can just be memcpy'd
into the reply buffer.
Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/fsinfo.c | 34 +++++++++++++++++++++
include/linux/fsinfo.h | 38 +++++++++++++++++++++++
include/uapi/linux/fsinfo.h | 68 ++++++++++++++++++++++++++++++++++++++++++
samples/vfs/test-fsinfo.c | 70 +++++++++++++++++++++++++++++++++++++++++++
4 files changed, 210 insertions(+)
diff --git a/fs/fsinfo.c b/fs/fsinfo.c
index 7d9c73e9cbde..79c222d465d8 100644
--- a/fs/fsinfo.c
+++ b/fs/fsinfo.c
@@ -131,6 +131,39 @@ int fsinfo_generic_supports(struct path *path, struct fsinfo_context *ctx)
}
EXPORT_SYMBOL(fsinfo_generic_supports);
+int fsinfo_generic_features(struct path *path, struct fsinfo_context *ctx)
+{
+ struct fsinfo_features *p = ctx->buffer;
+ struct super_block *sb = path->dentry->d_sb;
+
+ fsinfo_init_features(p);
+ if (sb->s_mtd)
+ fsinfo_set_feature(p, FSINFO_FEAT_IS_FLASH_FS);
+ else if (sb->s_bdev)
+ fsinfo_set_feature(p, FSINFO_FEAT_IS_BLOCK_FS);
+
+ if (sb->s_quota_types & QTYPE_MASK_USR)
+ fsinfo_set_feature(p, FSINFO_FEAT_USER_QUOTAS);
+ if (sb->s_quota_types & QTYPE_MASK_GRP)
+ fsinfo_set_feature(p, FSINFO_FEAT_GROUP_QUOTAS);
+ if (sb->s_quota_types & QTYPE_MASK_PRJ)
+ fsinfo_set_feature(p, FSINFO_FEAT_PROJECT_QUOTAS);
+ if (sb->s_d_op && sb->s_d_op->d_automount)
+ fsinfo_set_feature(p, FSINFO_FEAT_AUTOMOUNTS);
+ if (sb->s_id[0])
+ fsinfo_set_feature(p, FSINFO_FEAT_VOLUME_ID);
+ if (sb->s_flags & SB_MANDLOCK)
+ fsinfo_set_feature(p, FSINFO_FEAT_MAND_LOCKS);
+ if (sb->s_flags & SB_POSIXACL)
+ fsinfo_set_feature(p, FSINFO_FEAT_HAS_ACL);
+
+ fsinfo_set_feature(p, FSINFO_FEAT_HAS_ATIME);
+ fsinfo_set_feature(p, FSINFO_FEAT_HAS_CTIME);
+ fsinfo_set_feature(p, FSINFO_FEAT_HAS_MTIME);
+ return sizeof(*p);
+}
+EXPORT_SYMBOL(fsinfo_generic_features);
+
static const struct fsinfo_timestamp_info fsinfo_default_timestamp_info = {
.atime = {
.minimum = S64_MIN,
@@ -206,6 +239,7 @@ static const struct fsinfo_attribute fsinfo_common_attributes[] = {
FSINFO_VSTRUCT (FSINFO_ATTR_TIMESTAMP_INFO, fsinfo_generic_timestamp_info),
FSINFO_STRING (FSINFO_ATTR_VOLUME_ID, fsinfo_generic_volume_id),
FSINFO_VSTRUCT (FSINFO_ATTR_VOLUME_UUID, fsinfo_generic_volume_uuid),
+ FSINFO_VSTRUCT (FSINFO_ATTR_FEATURES, fsinfo_generic_features),
FSINFO_LIST (FSINFO_ATTR_FSINFO_ATTRIBUTES, (void *)123UL),
FSINFO_VSTRUCT_N(FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO, (void *)123UL),
diff --git a/include/linux/fsinfo.h b/include/linux/fsinfo.h
index a811d69b02ff..517edd5a2791 100644
--- a/include/linux/fsinfo.h
+++ b/include/linux/fsinfo.h
@@ -68,6 +68,44 @@ extern int fsinfo_generic_supports(struct path *, struct fsinfo_context *);
extern int fsinfo_generic_limits(struct path *, struct fsinfo_context *);
extern int fsinfo_get_attribute(struct path *, struct fsinfo_context *,
const struct fsinfo_attribute *);
+extern int fsinfo_generic_features(struct path *, struct fsinfo_context *);
+
+static inline void fsinfo_init_features(struct fsinfo_features *p)
+{
+ p->nr_features = FSINFO_FEAT__NR;
+}
+
+static inline void fsinfo_set_feature(struct fsinfo_features *p,
+ enum fsinfo_feature feature)
+{
+ p->features[feature / 8] |= 1 << (feature % 8);
+}
+
+static inline void fsinfo_clear_feature(struct fsinfo_features *p,
+ enum fsinfo_feature feature)
+{
+ p->features[feature / 8] &= ~(1 << (feature % 8));
+}
+
+/**
+ * fsinfo_set_unix_features - Set standard UNIX features.
+ * @f: The features mask to alter
+ */
+static inline void fsinfo_set_unix_features(struct fsinfo_features *p)
+{
+ fsinfo_set_feature(p, FSINFO_FEAT_UIDS);
+ fsinfo_set_feature(p, FSINFO_FEAT_GIDS);
+ fsinfo_set_feature(p, FSINFO_FEAT_DIRECTORIES);
+ fsinfo_set_feature(p, FSINFO_FEAT_SYMLINKS);
+ fsinfo_set_feature(p, FSINFO_FEAT_HARD_LINKS);
+ fsinfo_set_feature(p, FSINFO_FEAT_DEVICE_FILES);
+ fsinfo_set_feature(p, FSINFO_FEAT_UNIX_SPECIALS);
+ fsinfo_set_feature(p, FSINFO_FEAT_SPARSE);
+ fsinfo_set_feature(p, FSINFO_FEAT_HAS_ATIME);
+ fsinfo_set_feature(p, FSINFO_FEAT_HAS_CTIME);
+ fsinfo_set_feature(p, FSINFO_FEAT_HAS_MTIME);
+ fsinfo_set_feature(p, FSINFO_FEAT_HAS_INODE_NUMBERS);
+}
#endif /* CONFIG_FSINFO */
diff --git a/include/uapi/linux/fsinfo.h b/include/uapi/linux/fsinfo.h
index 65892239ba86..b8b2c836267b 100644
--- a/include/uapi/linux/fsinfo.h
+++ b/include/uapi/linux/fsinfo.h
@@ -23,6 +23,7 @@
#define FSINFO_ATTR_VOLUME_ID 0x05 /* Volume ID (string) */
#define FSINFO_ATTR_VOLUME_UUID 0x06 /* Volume UUID (LE uuid) */
#define FSINFO_ATTR_VOLUME_NAME 0x07 /* Volume name (string) */
+#define FSINFO_ATTR_FEATURES 0x08 /* Filesystem features (bits) */
#define FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO 0x100 /* Information about attr N (for path) */
#define FSINFO_ATTR_FSINFO_ATTRIBUTES 0x101 /* List of supported attrs (for path) */
@@ -157,6 +158,73 @@ struct fsinfo_supports {
#define FSINFO_ATTR_SUPPORTS__STRUCT struct fsinfo_supports
+/*
+ * Information struct for fsinfo(FSINFO_ATTR_FEATURES).
+ *
+ * Bitmask indicating filesystem features where renderable as single bits.
+ */
+enum fsinfo_feature {
+ FSINFO_FEAT_IS_KERNEL_FS = 0, /* fs is kernel-special filesystem */
+ FSINFO_FEAT_IS_BLOCK_FS = 1, /* fs is block-based filesystem */
+ FSINFO_FEAT_IS_FLASH_FS = 2, /* fs is flash filesystem */
+ FSINFO_FEAT_IS_NETWORK_FS = 3, /* fs is network filesystem */
+ FSINFO_FEAT_IS_AUTOMOUNTER_FS = 4, /* fs is automounter special filesystem */
+ FSINFO_FEAT_IS_MEMORY_FS = 5, /* fs is memory-based filesystem */
+ FSINFO_FEAT_AUTOMOUNTS = 6, /* fs supports automounts */
+ FSINFO_FEAT_ADV_LOCKS = 7, /* fs supports advisory file locking */
+ FSINFO_FEAT_MAND_LOCKS = 8, /* fs supports mandatory file locking */
+ FSINFO_FEAT_LEASES = 9, /* fs supports file leases */
+ FSINFO_FEAT_UIDS = 10, /* fs supports numeric uids */
+ FSINFO_FEAT_GIDS = 11, /* fs supports numeric gids */
+ FSINFO_FEAT_PROJIDS = 12, /* fs supports numeric project ids */
+ FSINFO_FEAT_STRING_USER_IDS = 13, /* fs supports string user identifiers */
+ FSINFO_FEAT_GUID_USER_IDS = 14, /* fs supports GUID user identifiers */
+ FSINFO_FEAT_WINDOWS_ATTRS = 15, /* fs has windows attributes */
+ FSINFO_FEAT_USER_QUOTAS = 16, /* fs has per-user quotas */
+ FSINFO_FEAT_GROUP_QUOTAS = 17, /* fs has per-group quotas */
+ FSINFO_FEAT_PROJECT_QUOTAS = 18, /* fs has per-project quotas */
+ FSINFO_FEAT_XATTRS = 19, /* fs has xattrs */
+ FSINFO_FEAT_JOURNAL = 20, /* fs has a journal */
+ FSINFO_FEAT_DATA_IS_JOURNALLED = 21, /* fs is using data journalling */
+ FSINFO_FEAT_O_SYNC = 22, /* fs supports O_SYNC */
+ FSINFO_FEAT_O_DIRECT = 23, /* fs supports O_DIRECT */
+ FSINFO_FEAT_VOLUME_ID = 24, /* fs has a volume ID */
+ FSINFO_FEAT_VOLUME_UUID = 25, /* fs has a volume UUID */
+ FSINFO_FEAT_VOLUME_NAME = 26, /* fs has a volume name */
+ FSINFO_FEAT_VOLUME_FSID = 27, /* fs has a volume FSID */
+ FSINFO_FEAT_IVER_ALL_CHANGE = 28, /* i_version represents data + meta changes */
+ FSINFO_FEAT_IVER_DATA_CHANGE = 29, /* i_version represents data changes only */
+ FSINFO_FEAT_IVER_MONO_INCR = 30, /* i_version incremented monotonically */
+ FSINFO_FEAT_DIRECTORIES = 31, /* fs supports (sub)directories */
+ FSINFO_FEAT_SYMLINKS = 32, /* fs supports symlinks */
+ FSINFO_FEAT_HARD_LINKS = 33, /* fs supports hard links */
+ FSINFO_FEAT_HARD_LINKS_1DIR = 34, /* fs supports hard links in same dir only */
+ FSINFO_FEAT_DEVICE_FILES = 35, /* fs supports bdev, cdev */
+ FSINFO_FEAT_UNIX_SPECIALS = 36, /* fs supports pipe, fifo, socket */
+ FSINFO_FEAT_RESOURCE_FORKS = 37, /* fs supports resource forks/streams */
+ FSINFO_FEAT_NAME_CASE_INDEP = 38, /* Filename case independence is mandatory */
+ FSINFO_FEAT_NAME_CASE_FOLD = 39, /* Filename case is folded on medium */
+ FSINFO_FEAT_NAME_NON_UTF8 = 40, /* fs has non-utf8 names */
+ FSINFO_FEAT_NAME_HAS_CODEPAGE = 41, /* fs has a filename codepage */
+ FSINFO_FEAT_SPARSE = 42, /* fs supports sparse files */
+ FSINFO_FEAT_NOT_PERSISTENT = 43, /* fs is not persistent */
+ FSINFO_FEAT_NO_UNIX_MODE = 44, /* fs does not support unix mode bits */
+ FSINFO_FEAT_HAS_ATIME = 45, /* fs supports access time */
+ FSINFO_FEAT_HAS_BTIME = 46, /* fs supports birth/creation time */
+ FSINFO_FEAT_HAS_CTIME = 47, /* fs supports change time */
+ FSINFO_FEAT_HAS_MTIME = 48, /* fs supports modification time */
+ FSINFO_FEAT_HAS_ACL = 49, /* fs supports ACLs of some sort */
+ FSINFO_FEAT_HAS_INODE_NUMBERS = 50, /* fs has inode numbers */
+ FSINFO_FEAT__NR
+};
+
+struct fsinfo_features {
+ __u32 nr_features; /* Number of supported features (FSINFO_FEAT__NR) */
+ __u8 features[(FSINFO_FEAT__NR + 7) / 8];
+};
+
+#define FSINFO_ATTR_FEATURES__STRUCT struct fsinfo_features
+
struct fsinfo_timestamp_one {
__s64 minimum; /* Minimum timestamp value in seconds */
__s64 maximum; /* Maximum timestamp value in seconds */
diff --git a/samples/vfs/test-fsinfo.c b/samples/vfs/test-fsinfo.c
index 934b25399ffe..c5932109f683 100644
--- a/samples/vfs/test-fsinfo.c
+++ b/samples/vfs/test-fsinfo.c
@@ -190,6 +190,75 @@ static void dump_fsinfo_generic_supports(void *reply, unsigned int size)
printf("\twin_fattrs : %x\n", f->win_file_attrs);
}
+#define FSINFO_FEATURE_NAME(C) [FSINFO_FEAT_##C] = #C
+static const char *fsinfo_feature_names[FSINFO_FEAT__NR] = {
+ FSINFO_FEATURE_NAME(IS_KERNEL_FS),
+ FSINFO_FEATURE_NAME(IS_BLOCK_FS),
+ FSINFO_FEATURE_NAME(IS_FLASH_FS),
+ FSINFO_FEATURE_NAME(IS_NETWORK_FS),
+ FSINFO_FEATURE_NAME(IS_AUTOMOUNTER_FS),
+ FSINFO_FEATURE_NAME(IS_MEMORY_FS),
+ FSINFO_FEATURE_NAME(AUTOMOUNTS),
+ FSINFO_FEATURE_NAME(ADV_LOCKS),
+ FSINFO_FEATURE_NAME(MAND_LOCKS),
+ FSINFO_FEATURE_NAME(LEASES),
+ FSINFO_FEATURE_NAME(UIDS),
+ FSINFO_FEATURE_NAME(GIDS),
+ FSINFO_FEATURE_NAME(PROJIDS),
+ FSINFO_FEATURE_NAME(STRING_USER_IDS),
+ FSINFO_FEATURE_NAME(GUID_USER_IDS),
+ FSINFO_FEATURE_NAME(WINDOWS_ATTRS),
+ FSINFO_FEATURE_NAME(USER_QUOTAS),
+ FSINFO_FEATURE_NAME(GROUP_QUOTAS),
+ FSINFO_FEATURE_NAME(PROJECT_QUOTAS),
+ FSINFO_FEATURE_NAME(XATTRS),
+ FSINFO_FEATURE_NAME(JOURNAL),
+ FSINFO_FEATURE_NAME(DATA_IS_JOURNALLED),
+ FSINFO_FEATURE_NAME(O_SYNC),
+ FSINFO_FEATURE_NAME(O_DIRECT),
+ FSINFO_FEATURE_NAME(VOLUME_ID),
+ FSINFO_FEATURE_NAME(VOLUME_UUID),
+ FSINFO_FEATURE_NAME(VOLUME_NAME),
+ FSINFO_FEATURE_NAME(VOLUME_FSID),
+ FSINFO_FEATURE_NAME(IVER_ALL_CHANGE),
+ FSINFO_FEATURE_NAME(IVER_DATA_CHANGE),
+ FSINFO_FEATURE_NAME(IVER_MONO_INCR),
+ FSINFO_FEATURE_NAME(DIRECTORIES),
+ FSINFO_FEATURE_NAME(SYMLINKS),
+ FSINFO_FEATURE_NAME(HARD_LINKS),
+ FSINFO_FEATURE_NAME(HARD_LINKS_1DIR),
+ FSINFO_FEATURE_NAME(DEVICE_FILES),
+ FSINFO_FEATURE_NAME(UNIX_SPECIALS),
+ FSINFO_FEATURE_NAME(RESOURCE_FORKS),
+ FSINFO_FEATURE_NAME(NAME_CASE_INDEP),
+ FSINFO_FEATURE_NAME(NAME_CASE_FOLD),
+ FSINFO_FEATURE_NAME(NAME_NON_UTF8),
+ FSINFO_FEATURE_NAME(NAME_HAS_CODEPAGE),
+ FSINFO_FEATURE_NAME(SPARSE),
+ FSINFO_FEATURE_NAME(NOT_PERSISTENT),
+ FSINFO_FEATURE_NAME(NO_UNIX_MODE),
+ FSINFO_FEATURE_NAME(HAS_ATIME),
+ FSINFO_FEATURE_NAME(HAS_BTIME),
+ FSINFO_FEATURE_NAME(HAS_CTIME),
+ FSINFO_FEATURE_NAME(HAS_MTIME),
+ FSINFO_FEATURE_NAME(HAS_ACL),
+ FSINFO_FEATURE_NAME(HAS_INODE_NUMBERS),
+};
+
+static void dump_fsinfo_generic_features(void *reply, unsigned int size)
+{
+ struct fsinfo_features *f = reply;
+ int i;
+
+ printf("\n\t");
+ for (i = 0; i < sizeof(f->features); i++)
+ printf("%02x", f->features[i]);
+ printf(" (nr=%u)\n", f->nr_features);
+ for (i = 0; i < FSINFO_FEAT__NR; i++)
+ if (f->features[i / 8] & (1 << (i % 8)))
+ printf("\t- %s\n", fsinfo_feature_names[i]);
+}
+
static void print_time(struct fsinfo_timestamp_one *t, char stamp)
{
printf("\t%ctime : gran=%uE%d range=%llx-%llx\n",
@@ -290,6 +359,7 @@ static const struct fsinfo_attribute fsinfo_attributes[] = {
FSINFO_VSTRUCT (FSINFO_ATTR_IDS, fsinfo_generic_ids),
FSINFO_VSTRUCT (FSINFO_ATTR_LIMITS, fsinfo_generic_limits),
FSINFO_VSTRUCT (FSINFO_ATTR_SUPPORTS, fsinfo_generic_supports),
+ FSINFO_VSTRUCT (FSINFO_ATTR_FEATURES, fsinfo_generic_features),
FSINFO_VSTRUCT (FSINFO_ATTR_TIMESTAMP_INFO, fsinfo_generic_timestamp_info),
FSINFO_STRING (FSINFO_ATTR_VOLUME_ID, string),
FSINFO_VSTRUCT (FSINFO_ATTR_VOLUME_UUID, fsinfo_generic_volume_uuid),
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