* [PATCH 1/5] vfs: syscall: Add fsinfo() to query filesystem information
2018-08-01 16:13 [PATCH 0/5] VFS: Introduce filesystem information query syscall David Howells
@ 2018-08-01 16:14 ` David Howells
2018-08-01 16:28 ` Theodore Y. Ts'o
2018-08-01 22:20 ` David Howells
2018-08-01 16:14 ` [PATCH 2/5] afs: Add fsinfo support David Howells
` (3 subsequent siblings)
4 siblings, 2 replies; 8+ messages in thread
From: David Howells @ 2018-08-01 16:14 UTC (permalink / raw)
To: viro; +Cc: linux-api, torvalds, dhowells, linux-fsdevel, linux-kernel
Add a system call to allow filesystem information to be queried. A request
value can be given to indicate the desired attribute. Support is provided
for enumerating multi-value attributes.
===============
NEW SYSTEM CALL
===============
The new system call looks like:
int ret = fsinfo(int dfd,
const char *filename,
const struct fsinfo_params *params,
void *buffer,
size_t buf_size);
The params parameter optionally points to a block of parameters:
struct fsinfo_params {
__u32 at_flags;
__u32 request;
__u32 Nth;
__u32 Mth;
__u32 __reserved[6];
};
If params is NULL, it is assumed params->request should be
fsinfo_attr_statfs, params->Nth should be 0, params->Mth should be 0 and
params->at_flags should be 0.
If params is given, all of params->__reserved[] must be 0.
dfd, filename and params->at_flags indicate the file to query. There is no
equivalent of lstat() as that can be emulated with fsinfo() by setting
AT_SYMLINK_NOFOLLOW in params->at_flags. There is also no equivalent of
fstat() as that can be emulated by passing a NULL filename to fsinfo() with
the fd of interest in dfd. AT_NO_AUTOMOUNT can also be used to an allow
automount point to be queried without triggering it.
params->request indicates the attribute/attributes to be queried. This can
be one of:
FSINFO_ATTR_STATFS - statfs-style info
FSINFO_ATTR_FSINFO - Information about fsinfo()
FSINFO_ATTR_IDS - Filesystem IDs
FSINFO_ATTR_LIMITS - Filesystem limits
FSINFO_ATTR_SUPPORTS - What's supported in statx(), IOC flags
FSINFO_ATTR_CAPABILITIES - Filesystem capabilities
FSINFO_ATTR_TIMESTAMP_INFO - Inode timestamp info
FSINFO_ATTR_VOLUME_ID - Volume ID (string)
FSINFO_ATTR_VOLUME_UUID - Volume UUID
FSINFO_ATTR_VOLUME_NAME - Volume name (string)
FSINFO_ATTR_CELL_NAME - Cell name (string)
FSINFO_ATTR_DOMAIN_NAME - Domain name (string)
FSINFO_ATTR_REALM_NAME - Realm name (string)
FSINFO_ATTR_SERVER_NAME - Name of the Nth server (string)
FSINFO_ATTR_SERVER_ADDRESS - Mth address of the Nth server
FSINFO_ATTR_PARAMETER - Nth mount parameter (string)
FSINFO_ATTR_SOURCE - Nth mount source name (string)
FSINFO_ATTR_NAME_ENCODING - Filename encoding (string)
FSINFO_ATTR_NAME_CODEPAGE - Filename codepage (string)
FSINFO_ATTR_IO_SIZE - I/O size hints
Some attributes (such as the servers backing a network filesystem) can have
multiple values. These can be enumerated by setting params->Nth and
params->Mth to 0, 1, ... until ENODATA is returned.
buffer and buf_size point to the reply buffer. The buffer is filled up to
the specified size, even if this means truncating the reply. The full size
of the reply is returned. In future versions, this will allow extra fields
to be tacked on to the end of the reply, but anyone not expecting them will
only get the subset they're expecting. If either buffer of buf_size are 0,
no copy will take place and the data size will be returned.
At the moment, this will only work on x86_64 and i386 as it requires the
system call to be wired up.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-api@vger.kernel.org
---
arch/x86/entry/syscalls/syscall_32.tbl | 1
arch/x86/entry/syscalls/syscall_64.tbl | 1
fs/statfs.c | 462 +++++++++++++++++++++++++++
include/linux/fs.h | 4
include/linux/fsinfo.h | 41 ++
include/linux/syscalls.h | 4
include/uapi/linux/fsinfo.h | 235 ++++++++++++++
samples/statx/Makefile | 5
samples/statx/test-fsinfo.c | 546 ++++++++++++++++++++++++++++++++
9 files changed, 1298 insertions(+), 1 deletion(-)
create mode 100644 include/linux/fsinfo.h
create mode 100644 include/uapi/linux/fsinfo.h
create mode 100644 samples/statx/test-fsinfo.c
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index d1eb6c815790..806760188a31 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -404,3 +404,4 @@
390 i386 fsconfig sys_fsconfig __ia32_sys_fsconfig
391 i386 fsmount sys_fsmount __ia32_sys_fsmount
392 i386 fspick sys_fspick __ia32_sys_fspick
+393 i386 fsinfo sys_fsinfo __ia32_sys_fsinfo
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index d3ab703c02bb..0823eed2b02e 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -349,6 +349,7 @@
338 common fsconfig __x64_sys_fsconfig
339 common fsmount __x64_sys_fsmount
340 common fspick __x64_sys_fspick
+341 common fsinfo __x64_sys_fsinfo
#
# x32-specific system call numbers start at 512 to avoid cache impact
diff --git a/fs/statfs.c b/fs/statfs.c
index 5b2a24f0f263..87826933faa0 100644
--- a/fs/statfs.c
+++ b/fs/statfs.c
@@ -9,6 +9,7 @@
#include <linux/security.h>
#include <linux/uaccess.h>
#include <linux/compat.h>
+#include <linux/fsinfo.h>
#include "internal.h"
static int flags_by_mnt(int mnt_flags)
@@ -384,3 +385,464 @@ COMPAT_SYSCALL_DEFINE2(ustat, unsigned, dev, struct compat_ustat __user *, u)
return 0;
}
#endif
+
+/*
+ * Get basic filesystem stats from statfs.
+ */
+static int fsinfo_generic_statfs(struct dentry *dentry,
+ struct fsinfo_statfs *p)
+{
+ struct super_block *sb;
+ struct kstatfs buf;
+ int ret;
+
+ ret = statfs_by_dentry(dentry, &buf);
+ if (ret < 0)
+ return ret;
+
+ sb = dentry->d_sb;
+ p->f_blocks = buf.f_blocks;
+ p->f_bfree = buf.f_bfree;
+ p->f_bavail = buf.f_bavail;
+ p->f_files = buf.f_files;
+ p->f_ffree = buf.f_ffree;
+ p->f_favail = buf.f_ffree;
+ p->f_bsize = buf.f_bsize;
+ p->f_frsize = buf.f_frsize;
+ return sizeof(*p);
+}
+
+static int fsinfo_generic_ids(struct dentry *dentry,
+ struct fsinfo_ids *p)
+{
+ struct super_block *sb;
+ struct kstatfs buf;
+ int ret;
+
+ ret = statfs_by_dentry(dentry, &buf);
+ if (ret < 0)
+ return ret;
+
+ sb = dentry->d_sb;
+ p->f_fstype = sb->s_magic;
+ p->f_dev_major = MAJOR(sb->s_dev);
+ p->f_dev_minor = MINOR(sb->s_dev);
+ p->f_flags = ST_VALID | flags_by_sb(sb->s_flags);
+
+ memcpy(&p->f_fsid, &buf.f_fsid, sizeof(p->f_fsid));
+ strlcpy(p->f_fs_name, dentry->d_sb->s_type->name, sizeof(p->f_fs_name));
+ return sizeof(*p);
+}
+
+static int fsinfo_generic_limits(struct dentry *dentry,
+ struct fsinfo_limits *lim)
+{
+ struct super_block *sb = dentry->d_sb;
+
+ lim->max_file_size = sb->s_maxbytes;
+ lim->max_hard_links = sb->s_max_links;
+ lim->max_uid = UINT_MAX;
+ lim->max_gid = UINT_MAX;
+ lim->max_projid = UINT_MAX;
+ lim->max_filename_len = NAME_MAX;
+ lim->max_symlink_len = PAGE_SIZE;
+ lim->max_xattr_name_len = XATTR_NAME_MAX;
+ lim->max_xattr_body_len = XATTR_SIZE_MAX;
+ lim->max_dev_major = 0xffffff;
+ lim->max_dev_minor = 0xff;
+ return sizeof(*lim);
+}
+
+static int fsinfo_generic_supports(struct dentry *dentry,
+ struct fsinfo_supports *c)
+{
+ struct super_block *sb = dentry->d_sb;
+
+ c->stx_mask = STATX_BASIC_STATS;
+ if (sb->s_d_op && sb->s_d_op->d_automount)
+ c->stx_attributes |= STATX_ATTR_AUTOMOUNT;
+ return sizeof(*c);
+}
+
+static int fsinfo_generic_capabilities(struct dentry *dentry,
+ struct fsinfo_capabilities *c)
+{
+ struct super_block *sb = dentry->d_sb;
+
+ if (sb->s_mtd)
+ fsinfo_set_cap(c, FSINFO_CAP_IS_FLASH_FS);
+ else if (sb->s_bdev)
+ fsinfo_set_cap(c, FSINFO_CAP_IS_BLOCK_FS);
+
+ if (sb->s_quota_types & QTYPE_MASK_USR)
+ fsinfo_set_cap(c, FSINFO_CAP_USER_QUOTAS);
+ if (sb->s_quota_types & QTYPE_MASK_GRP)
+ fsinfo_set_cap(c, FSINFO_CAP_GROUP_QUOTAS);
+ if (sb->s_quota_types & QTYPE_MASK_PRJ)
+ fsinfo_set_cap(c, FSINFO_CAP_PROJECT_QUOTAS);
+ if (sb->s_d_op && sb->s_d_op->d_automount)
+ fsinfo_set_cap(c, FSINFO_CAP_AUTOMOUNTS);
+ if (sb->s_id[0])
+ fsinfo_set_cap(c, FSINFO_CAP_VOLUME_ID);
+
+ fsinfo_set_cap(c, FSINFO_CAP_HAS_ATIME);
+ fsinfo_set_cap(c, FSINFO_CAP_HAS_CTIME);
+ fsinfo_set_cap(c, FSINFO_CAP_HAS_MTIME);
+ return sizeof(*c);
+}
+
+static int fsinfo_generic_timestamp_info(struct dentry *dentry,
+ struct fsinfo_timestamp_info *ts)
+{
+ struct super_block *sb = dentry->d_sb;
+
+ /* If unset, assume 1s granularity */
+ u16 mantissa = 1;
+ s8 exponent = 0;
+
+ ts->minimum_timestamp = S64_MIN;
+ ts->maximum_timestamp = S64_MAX;
+ if (sb->s_time_gran < 1000000000) {
+ if (sb->s_time_gran < 1000)
+ exponent = -9;
+ else if (sb->s_time_gran < 1000000)
+ exponent = -6;
+ else
+ exponent = -3;
+ }
+#define set_gran(x) \
+ do { \
+ ts->x##_mantissa = mantissa; \
+ ts->x##_exponent = exponent; \
+ } while (0)
+ set_gran(atime_gran);
+ set_gran(btime_gran);
+ set_gran(ctime_gran);
+ set_gran(mtime_gran);
+ return sizeof(*ts);
+}
+
+static int fsinfo_generic_volume_uuid(struct dentry *dentry,
+ struct fsinfo_volume_uuid *vu)
+{
+ struct super_block *sb = dentry->d_sb;
+
+ memcpy(vu, &sb->s_uuid, sizeof(*vu));
+ return sizeof(*vu);
+}
+
+static int fsinfo_generic_volume_id(struct dentry *dentry, char *buf)
+{
+ struct super_block *sb = dentry->d_sb;
+ size_t len = strlen(sb->s_id);
+
+ memcpy(buf, sb->s_id, len + 1);
+ return len;
+}
+
+static int fsinfo_generic_name_encoding(struct dentry *dentry, char *buf)
+{
+ static const char encoding[] = "utf8";
+
+ memcpy(buf, encoding, sizeof(encoding) - 1);
+ return sizeof(encoding) - 1;
+}
+
+static int fsinfo_generic_io_size(struct dentry *dentry,
+ struct fsinfo_io_size *c)
+{
+ struct super_block *sb = dentry->d_sb;
+ struct kstatfs buf;
+ int ret;
+
+ if (sb->s_op->statfs == simple_statfs) {
+ c->dio_size_gran = 1;
+ c->dio_mem_align = 1;
+ } else {
+ ret = statfs_by_dentry(dentry, &buf);
+ if (ret < 0)
+ return ret;
+ c->dio_size_gran = buf.f_bsize;
+ c->dio_mem_align = buf.f_bsize;
+ }
+ return sizeof(*c);
+}
+
+/*
+ * Implement some queries generically from stuff in the superblock.
+ */
+int generic_fsinfo(struct dentry *dentry, struct fsinfo_kparams *params)
+{
+#define _gen(X, Y) FSINFO_ATTR_##X: return fsinfo_generic_##Y(dentry, params->buffer)
+
+ switch (params->request) {
+ case _gen(STATFS, statfs);
+ case _gen(IDS, ids);
+ case _gen(LIMITS, limits);
+ case _gen(SUPPORTS, supports);
+ case _gen(CAPABILITIES, capabilities);
+ case _gen(TIMESTAMP_INFO, timestamp_info);
+ case _gen(VOLUME_UUID, volume_uuid);
+ case _gen(VOLUME_ID, volume_id);
+ case _gen(NAME_ENCODING, name_encoding);
+ case _gen(IO_SIZE, io_size);
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+EXPORT_SYMBOL(generic_fsinfo);
+
+/*
+ * Retrieve the filesystem info. We make some stuff up if the operation is not
+ * supported.
+ */
+int vfs_fsinfo(const struct path *path, struct fsinfo_kparams *params)
+{
+ struct dentry *dentry = path->dentry;
+ int (*get_fsinfo)(struct dentry *, struct fsinfo_kparams *);
+ int ret;
+
+ if (params->request == FSINFO_ATTR_FSINFO) {
+ struct fsinfo_fsinfo *info = params->buffer;
+
+ info->max_attr = FSINFO_ATTR__NR;
+ info->max_cap = FSINFO_CAP__NR;
+ return sizeof(*info);
+ }
+
+ get_fsinfo = dentry->d_sb->s_op->get_fsinfo;
+ if (!get_fsinfo) {
+ if (!dentry->d_sb->s_op->statfs)
+ return -EOPNOTSUPP;
+ get_fsinfo = generic_fsinfo;
+ }
+
+ ret = security_sb_statfs(dentry);
+ if (ret)
+ return ret;
+
+ ret = get_fsinfo(dentry, params);
+ if (ret < 0)
+ return ret;
+
+ if (params->request == FSINFO_ATTR_IDS &&
+ params->buffer) {
+ struct fsinfo_ids *p = params->buffer;
+
+ p->f_flags |= flags_by_mnt(path->mnt->mnt_flags);
+ }
+ return ret;
+}
+
+static int vfs_fsinfo_path(int dfd, const char __user *filename,
+ struct fsinfo_kparams *params)
+{
+ struct path path;
+ unsigned lookup_flags = LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT;
+ int ret = -EINVAL;
+
+ if ((params->at_flags & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT |
+ AT_EMPTY_PATH)) != 0)
+ return -EINVAL;
+
+ if (params->at_flags & AT_SYMLINK_NOFOLLOW)
+ lookup_flags &= ~LOOKUP_FOLLOW;
+ if (params->at_flags & AT_NO_AUTOMOUNT)
+ lookup_flags &= ~LOOKUP_AUTOMOUNT;
+ if (params->at_flags & AT_EMPTY_PATH)
+ lookup_flags |= LOOKUP_EMPTY;
+
+retry:
+ ret = user_path_at(dfd, filename, lookup_flags, &path);
+ if (ret)
+ goto out;
+
+ ret = vfs_fsinfo(&path, params);
+ path_put(&path);
+ if (retry_estale(ret, lookup_flags)) {
+ lookup_flags |= LOOKUP_REVAL;
+ goto retry;
+ }
+out:
+ return ret;
+}
+
+static int vfs_fsinfo_fd(unsigned int fd, struct fsinfo_kparams *params)
+{
+ struct fd f = fdget_raw(fd);
+ int ret = -EBADF;
+
+ if (f.file) {
+ ret = vfs_fsinfo(&f.file->f_path, params);
+ fdput(f);
+ }
+ return ret;
+}
+
+/*
+ * Return buffer information by requestable attribute.
+ *
+ * STRUCT indicates a fixed-size structure with only one instance.
+ * STRUCT_N indicates a 1D array of STRUCT, indexed by Nth
+ * STRUCT_NM indicates a 2D-array of STRUCT, indexed by Nth, Mth
+ * STRING indicates a string with only one instance.
+ * STRING_N indicates a 1D array of STRING, indexed by Nth
+ * STRING_NM indicates a 2D-array of STRING, indexed by Nth, Mth
+ *
+ * If an entry is marked STRUCT, STRUCT_N or STRUCT_NM then if no buffer is
+ * supplied to sys_fsinfo(), sys_fsinfo() will handle returning the buffer size
+ * without calling vfs_fsinfo() and the filesystem.
+ *
+ * No struct may have more than 252 bytes (ie. 0x3f * 4)
+ */
+#define FSINFO_STRING(X,Y) [FSINFO_ATTR_##X] = 0x0000
+#define FSINFO_STRUCT(X,Y) [FSINFO_ATTR_##X] = sizeof(struct fsinfo_##Y)
+#define FSINFO_STRING_N(X,Y) [FSINFO_ATTR_##X] = 0x4000
+#define FSINFO_STRUCT_N(X,Y) [FSINFO_ATTR_##X] = 0x4000 | sizeof(struct fsinfo_##Y)
+#define FSINFO_STRUCT_NM(X,Y) [FSINFO_ATTR_##X] = 0x8000 | sizeof(struct fsinfo_##Y)
+#define FSINFO_STRING_NM(X,Y) [FSINFO_ATTR_##X] = 0x8000
+static const u16 fsinfo_buffer_sizes[FSINFO_ATTR__NR] = {
+ FSINFO_STRUCT (STATFS, statfs),
+ FSINFO_STRUCT (FSINFO, fsinfo),
+ FSINFO_STRUCT (IDS, ids),
+ FSINFO_STRUCT (LIMITS, limits),
+ FSINFO_STRUCT (CAPABILITIES, capabilities),
+ FSINFO_STRUCT (SUPPORTS, supports),
+ FSINFO_STRUCT (TIMESTAMP_INFO, timestamp_info),
+ FSINFO_STRING (VOLUME_ID, volume_id),
+ FSINFO_STRUCT (VOLUME_UUID, volume_uuid),
+ FSINFO_STRING (VOLUME_NAME, volume_name),
+ FSINFO_STRING (CELL_NAME, cell_name),
+ FSINFO_STRING (DOMAIN_NAME, domain_name),
+ FSINFO_STRING (REALM_NAME, realm_name),
+ FSINFO_STRING_N (SERVER_NAME, server_name),
+ FSINFO_STRUCT_NM (SERVER_ADDRESS, server_address),
+ FSINFO_STRING_NM (PARAMETER, parameter),
+ FSINFO_STRING_N (SOURCE, source),
+ FSINFO_STRING (NAME_ENCODING, name_encoding),
+ FSINFO_STRING (NAME_CODEPAGE, name_codepage),
+ FSINFO_STRUCT (IO_SIZE, io_size),
+};
+
+/**
+ * sys_fsinfo - System call to get filesystem information
+ * @dfd: Base directory to pathwalk from or fd referring to filesystem.
+ * @filename: Filesystem to query or NULL.
+ * @_params: Parameters to define request (or NULL for enhanced statfs).
+ * @_buffer: Result buffer.
+ * @buf_size: Size of result buffer.
+ *
+ * Get information on a filesystem. The filesystem attribute to be queried is
+ * indicated by @_params->request, and some of the attributes can have multiple
+ * values, indexed by @_params->Nth and @_params->Mth. If @_params is NULL,
+ * then the 0th fsinfo_attr_statfs attribute is queried. If an attribute does
+ * not exist, EOPNOTSUPP is returned; if the Nth,Mth value does not exist,
+ * ENODATA is returned.
+ *
+ * On success, the size of the attribute's value is returned. If @buf_size is
+ * 0 or @_buffer is NULL, only the size is returned. If the size of the value
+ * is larger than @buf_size, it will be truncated by the copy. If the size of
+ * the value is smaller than @buf_size then the excess buffer space will be
+ * cleared. The full size of the value will be returned, irrespective of how
+ * much data is actually placed in the buffer.
+ */
+SYSCALL_DEFINE5(fsinfo,
+ int, dfd, const char __user *, filename,
+ struct fsinfo_params __user *, _params,
+ void __user *, _buffer, size_t, buf_size)
+{
+ struct fsinfo_params user_params;
+ struct fsinfo_kparams params;
+ size_t size, n;
+ int ret;
+
+ if (_params) {
+ if (copy_from_user(&user_params, _params, sizeof(user_params)))
+ return -EFAULT;
+ if (user_params.__reserved[0] ||
+ user_params.__reserved[1] ||
+ user_params.__reserved[2] ||
+ user_params.__reserved[3] ||
+ user_params.__reserved[4] ||
+ user_params.__reserved[5])
+ return -EINVAL;
+ if (user_params.request >= FSINFO_ATTR__NR)
+ return -EOPNOTSUPP;
+ params.at_flags = user_params.at_flags;
+ params.request = user_params.request;
+ params.Nth = user_params.Nth;
+ params.Mth = user_params.Mth;
+ } else {
+ params.at_flags = 0;
+ params.request = FSINFO_ATTR_STATFS;
+ params.Nth = 0;
+ params.Mth = 0;
+ }
+
+ if (!_buffer || !buf_size) {
+ buf_size = 0;
+ _buffer = NULL;
+ }
+
+ /* Allocate an appropriately-sized buffer. We will truncate the
+ * contents when we write the contents back to userspace.
+ */
+ size = fsinfo_buffer_sizes[params.request];
+ switch (size & 0xc000) {
+ case 0x0000:
+ if (params.Nth != 0)
+ return -ENODATA;
+ /* Fall through */
+ case 0x4000:
+ if (params.Mth != 0)
+ return -ENODATA;
+ /* Fall through */
+ case 0x8000:
+ break;
+ case 0xc000:
+ return -ENOBUFS;
+ }
+
+ size &= ~0xc000;
+ if (size == 0) {
+ params.string_val = true;
+ params.buf_size = 4096;
+ } else {
+ params.string_val = false;
+ params.buf_size = size;
+ if (buf_size == 0)
+ return size; /* We know how big the buffer should be */
+ }
+
+ /* We always allocate a buffer for a string, even if buf_size == 0 and
+ * we're not going to return any data. This means that the filesystem
+ * code needn't care about whether the buffer actually exists or not.
+ */
+ params.buffer = kzalloc(params.buf_size, GFP_KERNEL);
+ if (!params.buffer)
+ return -ENOMEM;
+
+ if (filename)
+ ret = vfs_fsinfo_path(dfd, filename, ¶ms);
+ else
+ ret = vfs_fsinfo_fd(dfd, ¶ms);
+ if (ret < 0)
+ goto error;
+
+ n = ret;
+ if (n > buf_size)
+ n = buf_size;
+
+ if (n > 0 && copy_to_user(_buffer, params.buffer, buf_size))
+ ret = -EFAULT;
+
+ /* Clear any part of the buffer that we won't fill if we're putting a
+ * struct in there rather than a string.
+ */
+ if (buf_size > n && !params.string_val &&
+ clear_user(_buffer + n, buf_size - n) != 0)
+ return -EFAULT;
+error:
+ kfree(params.buffer);
+ return ret;
+}
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 3e661d033163..053d53861995 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -64,6 +64,8 @@ struct fscrypt_operations;
struct fs_context;
struct fsconfig_parser;
struct fsconfig_param;
+struct fsinfo_kparams;
+enum fsinfo_attribute;
extern void __init inode_init(void);
extern void __init inode_init_early(void);
@@ -1849,6 +1851,7 @@ struct super_operations {
int (*thaw_super) (struct super_block *);
int (*unfreeze_fs) (struct super_block *);
int (*statfs) (struct dentry *, struct kstatfs *);
+ int (*get_fsinfo) (struct dentry *, struct fsinfo_kparams *);
int (*remount_fs) (struct super_block *, int *, char *, size_t);
int (*reconfigure) (struct super_block *, struct fs_context *);
void (*umount_begin) (struct super_block *);
@@ -2226,6 +2229,7 @@ extern int iterate_mounts(int (*)(struct vfsmount *, void *), void *,
extern int vfs_statfs(const struct path *, struct kstatfs *);
extern int user_statfs(const char __user *, struct kstatfs *);
extern int fd_statfs(int, struct kstatfs *);
+extern int vfs_fsinfo(const struct path *, struct fsinfo_kparams *);
extern int freeze_super(struct super_block *super);
extern int thaw_super(struct super_block *super);
extern bool our_mnt(struct vfsmount *mnt);
diff --git a/include/linux/fsinfo.h b/include/linux/fsinfo.h
new file mode 100644
index 000000000000..f2d25b898d48
--- /dev/null
+++ b/include/linux/fsinfo.h
@@ -0,0 +1,41 @@
+/* Filesystem information query
+ *
+ * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#ifndef _LINUX_FSINFO_H
+#define _LINUX_FSINFO_H
+
+#include <uapi/linux/fsinfo.h>
+
+struct fsinfo_kparams {
+ __u32 at_flags; /* AT_SYMLINK_NOFOLLOW and similar */
+ enum fsinfo_attribute request; /* What is being asking for */
+ __u32 Nth; /* Instance of it (some may have multiple) */
+ __u32 Mth; /* Subinstance */
+ bool string_val; /* T if variable-length string value */
+ void *buffer; /* Where to place the reply */
+ size_t buf_size; /* Size of the buffer */
+};
+
+extern int generic_fsinfo(struct dentry *, struct fsinfo_kparams *);
+
+static inline void fsinfo_set_cap(struct fsinfo_capabilities *c,
+ enum fsinfo_capability cap)
+{
+ c->capabilities[cap / 8] |= 1 << (cap % 8);
+}
+
+static inline void fsinfo_clear_cap(struct fsinfo_capabilities *c,
+ enum fsinfo_capability cap)
+{
+ c->capabilities[cap / 8] &= ~(1 << (cap % 8));
+}
+
+#endif /* _LINUX_FSINFO_H */
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 701522957a12..bc7173c09f4d 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -49,6 +49,7 @@ struct stat64;
struct statfs;
struct statfs64;
struct statx;
+struct fsinfo_params;
struct __sysctl_args;
struct sysinfo;
struct timespec;
@@ -909,6 +910,9 @@ asmlinkage long sys_fsconfig(int fs_fd, unsigned int cmd, const char __user *key
const void __user *value, int aux);
asmlinkage long sys_fsmount(int fs_fd, unsigned int flags, unsigned int ms_flags);
asmlinkage long sys_fspick(int dfd, const char __user *path, unsigned int flags);
+asmlinkage long sys_fsinfo(int dfd, const char __user *path,
+ struct fsinfo_params __user *params,
+ void __user *buffer, size_t buf_size);
/*
* Architecture-specific system calls
diff --git a/include/uapi/linux/fsinfo.h b/include/uapi/linux/fsinfo.h
new file mode 100644
index 000000000000..ca82cfb5f38a
--- /dev/null
+++ b/include/uapi/linux/fsinfo.h
@@ -0,0 +1,235 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/* fsinfo() definitions.
+ *
+ * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+#ifndef _UAPI_LINUX_FSINFO_H
+#define _UAPI_LINUX_FSINFO_H
+
+#include <linux/types.h>
+#include <linux/socket.h>
+
+/*
+ * The filesystem attributes that can be requested. Note that some attributes
+ * may have multiple instances which can be switched in the parameter block.
+ */
+enum fsinfo_attribute {
+ FSINFO_ATTR_STATFS = 0, /* statfs()-style state */
+ FSINFO_ATTR_FSINFO = 1, /* Information about fsinfo() */
+ FSINFO_ATTR_IDS = 2, /* Filesystem IDs */
+ FSINFO_ATTR_LIMITS = 3, /* Filesystem limits */
+ FSINFO_ATTR_SUPPORTS = 4, /* What's supported in statx, iocflags, ... */
+ FSINFO_ATTR_CAPABILITIES = 5, /* Filesystem capabilities (bits) */
+ FSINFO_ATTR_TIMESTAMP_INFO = 6, /* Inode timestamp info */
+ FSINFO_ATTR_VOLUME_ID = 7, /* Volume ID (string) */
+ FSINFO_ATTR_VOLUME_UUID = 8, /* Volume UUID (LE uuid) */
+ FSINFO_ATTR_VOLUME_NAME = 9, /* Volume name (string) */
+ FSINFO_ATTR_CELL_NAME = 10, /* Cell name (string) */
+ FSINFO_ATTR_DOMAIN_NAME = 11, /* Domain name (string) */
+ FSINFO_ATTR_REALM_NAME = 12, /* Realm name (string) */
+ FSINFO_ATTR_SERVER_NAME = 13, /* Name of the Nth server */
+ FSINFO_ATTR_SERVER_ADDRESS = 14, /* Mth address of the Nth server */
+ FSINFO_ATTR_PARAMETER = 15, /* Nth mount parameter (string) */
+ FSINFO_ATTR_SOURCE = 16, /* Nth mount source name (string) */
+ FSINFO_ATTR_NAME_ENCODING = 17, /* Filename encoding (string) */
+ FSINFO_ATTR_NAME_CODEPAGE = 18, /* Filename codepage (string) */
+ FSINFO_ATTR_IO_SIZE = 19, /* Optimal I/O sizes */
+ FSINFO_ATTR__NR
+};
+
+/*
+ * Optional fsinfo() parameter structure.
+ *
+ * If this is not given, it is assumed that fsinfo_attr_statfs instance 0,0 is
+ * desired.
+ */
+struct fsinfo_params {
+ __u32 at_flags; /* AT_SYMLINK_NOFOLLOW and similar flags */
+ __u32 request; /* What is being asking for (enum fsinfo_attribute) */
+ __u32 Nth; /* Instance of it (some may have multiple) */
+ __u32 Mth; /* Subinstance of Nth instance */
+ __u32 __reserved[6]; /* Reserved params; all must be 0 */
+};
+
+/*
+ * Information struct for fsinfo(fsinfo_attr_statfs).
+ * - This gives extended filesystem information.
+ */
+struct fsinfo_statfs {
+ __u64 f_blocks; /* Total number of blocks in fs */
+ __u64 f_bfree; /* Total number of free blocks */
+ __u64 f_bavail; /* Number of free blocks available to ordinary user */
+ __u64 f_files; /* Total number of file nodes in fs */
+ __u64 f_ffree; /* Number of free file nodes */
+ __u64 f_favail; /* Number of free file nodes available to ordinary user */
+ __u32 f_bsize; /* Optimal block size */
+ __u32 f_frsize; /* Fragment size */
+};
+
+/*
+ * Information struct for fsinfo(fsinfo_attr_ids).
+ *
+ * List of basic identifiers as is normally found in statfs().
+ */
+struct fsinfo_ids {
+ char f_fs_name[15 + 1];
+ __u64 f_flags; /* Filesystem mount flags (MS_*) */
+ __u64 f_fsid; /* Short 64-bit Filesystem ID (as statfs) */
+ __u64 f_sb_id; /* Internal superblock ID for sbnotify()/mntnotify() */
+ __u32 f_fstype; /* Filesystem type from linux/magic.h [uncond] */
+ __u32 f_dev_major; /* As st_dev_* from struct statx [uncond] */
+ __u32 f_dev_minor;
+ __u32 __reserved[1];
+};
+
+/*
+ * Information struct for fsinfo(fsinfo_attr_limits).
+ *
+ * List of supported filesystem limits.
+ */
+struct fsinfo_limits {
+ __u64 max_file_size; /* Maximum file size */
+ __u64 max_uid; /* Maximum UID supported */
+ __u64 max_gid; /* Maximum GID supported */
+ __u64 max_projid; /* Maximum project ID supported */
+ __u32 max_dev_major; /* Maximum device major representable */
+ __u32 max_dev_minor; /* Maximum device minor representable */
+ __u32 max_hard_links; /* Maximum number of hard links on a file */
+ __u32 max_xattr_body_len; /* Maximum xattr content length */
+ __u32 max_xattr_name_len; /* Maximum xattr name length */
+ __u32 max_filename_len; /* Maximum filename length */
+ __u32 max_symlink_len; /* Maximum symlink content length */
+ __u32 __reserved[1];
+};
+
+/*
+ * Information struct for fsinfo(fsinfo_attr_supports).
+ *
+ * What's supported in various masks, such as statx() attribute and mask bits
+ * and IOC flags.
+ */
+struct fsinfo_supports {
+ __u64 stx_attributes; /* What statx::stx_attributes are supported */
+ __u32 stx_mask; /* What statx::stx_mask bits are supported */
+ __u32 ioc_flags; /* What FS_IOC_* flags are supported */
+ __u32 win_file_attrs; /* What DOS/Windows FILE_* attributes are supported */
+ __u32 __reserved[1];
+};
+
+/*
+ * Information struct for fsinfo(fsinfo_attr_capabilities).
+ *
+ * Bitmask indicating filesystem capabilities where renderable as single bits.
+ */
+enum fsinfo_capability {
+ FSINFO_CAP_IS_KERNEL_FS = 0, /* fs is kernel-special filesystem */
+ FSINFO_CAP_IS_BLOCK_FS = 1, /* fs is block-based filesystem */
+ FSINFO_CAP_IS_FLASH_FS = 2, /* fs is flash filesystem */
+ FSINFO_CAP_IS_NETWORK_FS = 3, /* fs is network filesystem */
+ FSINFO_CAP_IS_AUTOMOUNTER_FS = 4, /* fs is automounter special filesystem */
+ FSINFO_CAP_AUTOMOUNTS = 5, /* fs supports automounts */
+ FSINFO_CAP_ADV_LOCKS = 6, /* fs supports advisory file locking */
+ FSINFO_CAP_MAND_LOCKS = 7, /* fs supports mandatory file locking */
+ FSINFO_CAP_LEASES = 8, /* fs supports file leases */
+ FSINFO_CAP_UIDS = 9, /* fs supports numeric uids */
+ FSINFO_CAP_GIDS = 10, /* fs supports numeric gids */
+ FSINFO_CAP_PROJIDS = 11, /* fs supports numeric project ids */
+ FSINFO_CAP_ID_NAMES = 12, /* fs supports user names */
+ FSINFO_CAP_ID_GUIDS = 13, /* fs supports user guids */
+ FSINFO_CAP_WINDOWS_ATTRS = 14, /* fs has windows attributes */
+ FSINFO_CAP_USER_QUOTAS = 15, /* fs has per-user quotas */
+ FSINFO_CAP_GROUP_QUOTAS = 16, /* fs has per-group quotas */
+ FSINFO_CAP_PROJECT_QUOTAS = 17, /* fs has per-project quotas */
+ FSINFO_CAP_XATTRS = 18, /* fs has xattrs */
+ FSINFO_CAP_JOURNAL = 19, /* fs has a journal */
+ FSINFO_CAP_DATA_IS_JOURNALLED = 20, /* fs is using data journalling */
+ FSINFO_CAP_O_SYNC = 21, /* fs supports O_SYNC */
+ FSINFO_CAP_O_DIRECT = 22, /* fs supports O_DIRECT */
+ FSINFO_CAP_VOLUME_ID = 23, /* fs has a volume ID */
+ FSINFO_CAP_VOLUME_UUID = 24, /* fs has a volume UUID */
+ FSINFO_CAP_VOLUME_NAME = 25, /* fs has a volume name */
+ FSINFO_CAP_VOLUME_FSID = 26, /* fs has a volume FSID */
+ FSINFO_CAP_CELL_NAME = 27, /* fs has a cell name */
+ FSINFO_CAP_DOMAIN_NAME = 28, /* fs has a domain name */
+ FSINFO_CAP_REALM_NAME = 29, /* fs has a realm name */
+ FSINFO_CAP_IVER_ALL_CHANGE = 30, /* i_version represents data + meta changes */
+ FSINFO_CAP_IVER_DATA_CHANGE = 31, /* i_version represents data changes only */
+ FSINFO_CAP_IVER_MONO_INCR = 32, /* i_version incremented monotonically */
+ FSINFO_CAP_SYMLINKS = 33, /* fs supports symlinks */
+ FSINFO_CAP_HARD_LINKS = 34, /* fs supports hard links */
+ FSINFO_CAP_HARD_LINKS_1DIR = 35, /* fs supports hard links in same dir only */
+ FSINFO_CAP_DEVICE_FILES = 36, /* fs supports bdev, cdev */
+ FSINFO_CAP_UNIX_SPECIALS = 37, /* fs supports pipe, fifo, socket */
+ FSINFO_CAP_RESOURCE_FORKS = 38, /* fs supports resource forks/streams */
+ FSINFO_CAP_NAME_CASE_INDEP = 39, /* Filename case independence is mandatory */
+ FSINFO_CAP_NAME_NON_UTF8 = 40, /* fs has non-utf8 names */
+ FSINFO_CAP_NAME_HAS_CODEPAGE = 41, /* fs has a filename codepage */
+ FSINFO_CAP_SPARSE = 42, /* fs supports sparse files */
+ FSINFO_CAP_NOT_PERSISTENT = 43, /* fs is not persistent */
+ FSINFO_CAP_NO_UNIX_MODE = 44, /* fs does not support unix mode bits */
+ FSINFO_CAP_HAS_ATIME = 45, /* fs supports access time */
+ FSINFO_CAP_HAS_BTIME = 46, /* fs supports birth/creation time */
+ FSINFO_CAP_HAS_CTIME = 47, /* fs supports change time */
+ FSINFO_CAP_HAS_MTIME = 48, /* fs supports modification time */
+ FSINFO_CAP__NR
+};
+
+struct fsinfo_capabilities {
+ __u8 capabilities[(FSINFO_CAP__NR + 7) / 8];
+};
+
+/*
+ * Information struct for fsinfo(fsinfo_attr_timestamp_info).
+ */
+struct fsinfo_timestamp_info {
+ __s64 minimum_timestamp; /* Minimum timestamp value in seconds */
+ __s64 maximum_timestamp; /* Maximum timestamp value in seconds */
+ __u16 atime_gran_mantissa; /* Granularity(secs) = mant * 10^exp */
+ __u16 btime_gran_mantissa;
+ __u16 ctime_gran_mantissa;
+ __u16 mtime_gran_mantissa;
+ __s8 atime_gran_exponent;
+ __s8 btime_gran_exponent;
+ __s8 ctime_gran_exponent;
+ __s8 mtime_gran_exponent;
+ __u32 __reserved[1];
+};
+
+/*
+ * Information struct for fsinfo(fsinfo_attr_volume_uuid).
+ */
+struct fsinfo_volume_uuid {
+ __u8 uuid[16];
+};
+
+/*
+ * Information struct for fsinfo(fsinfo_attr_server_addresses).
+ *
+ * Find the Mth address of the Nth server for a network mount.
+ */
+struct fsinfo_server_address {
+ struct __kernel_sockaddr_storage address;
+};
+
+/*
+ * Information struct for fsinfo(fsinfo_attr_io_size).
+ *
+ * Retrieve I/O size hints for a filesystem.
+ */
+struct fsinfo_io_size {
+ __u32 dio_size_gran; /* Size granularity for O_DIRECT */
+ __u32 dio_mem_align; /* Memory alignment for O_DIRECT */
+};
+
+/*
+ * Information struct for fsinfo(fsinfo_attr_fsinfo).
+ *
+ * This gives information about fsinfo() itself.
+ */
+struct fsinfo_fsinfo {
+ __u32 max_attr; /* Number of supported attributes (fsinfo_attr__nr) */
+ __u32 max_cap; /* Number of supported capabilities (fsinfo_cap__nr) */
+};
+
+#endif /* _UAPI_LINUX_FSINFO_H */
diff --git a/samples/statx/Makefile b/samples/statx/Makefile
index 59df7c25a9d1..9cb9a88e3a10 100644
--- a/samples/statx/Makefile
+++ b/samples/statx/Makefile
@@ -1,7 +1,10 @@
# List of programs to build
-hostprogs-$(CONFIG_SAMPLE_STATX) := test-statx
+hostprogs-$(CONFIG_SAMPLE_STATX) := test-statx test-fsinfo
# Tell kbuild to always build the programs
always := $(hostprogs-y)
HOSTCFLAGS_test-statx.o += -I$(objtree)/usr/include
+
+HOSTCFLAGS_test-fsinfo.o += -I$(objtree)/usr/include
+HOSTLOADLIBES_test-fsinfo += -lm
diff --git a/samples/statx/test-fsinfo.c b/samples/statx/test-fsinfo.c
new file mode 100644
index 000000000000..5fb3dcccff26
--- /dev/null
+++ b/samples/statx/test-fsinfo.c
@@ -0,0 +1,546 @@
+/* Test the fsinfo() system call
+ *
+ * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#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 <fcntl.h>
+#include <sys/syscall.h>
+#include <linux/fsinfo.h>
+#include <linux/socket.h>
+#include <sys/stat.h>
+
+static bool debug = 0;
+
+static __attribute__((unused))
+ssize_t fsinfo(int dfd, const char *filename, struct fsinfo_params *params,
+ void *buffer, size_t buf_size)
+{
+ return syscall(__NR_fsinfo, dfd, filename, params, buffer, buf_size);
+}
+
+#define FSINFO_STRING(X,Y) [FSINFO_ATTR_##X] = 0x0000
+#define FSINFO_STRUCT(X,Y) [FSINFO_ATTR_##X] = sizeof(struct fsinfo_##Y)
+#define FSINFO_STRING_N(X,Y) [FSINFO_ATTR_##X] = 0x4000
+#define FSINFO_STRUCT_N(X,Y) [FSINFO_ATTR_##X] = 0x4000 | sizeof(struct fsinfo_##Y)
+#define FSINFO_STRUCT_NM(X,Y) [FSINFO_ATTR_##X] = 0x8000 | sizeof(struct fsinfo_##Y)
+#define FSINFO_STRING_NM(X,Y) [FSINFO_ATTR_##X] = 0x8000
+static const __u16 fsinfo_buffer_sizes[FSINFO_ATTR__NR] = {
+ FSINFO_STRUCT (STATFS, statfs),
+ FSINFO_STRUCT (FSINFO, fsinfo),
+ FSINFO_STRUCT (IDS, ids),
+ FSINFO_STRUCT (LIMITS, limits),
+ FSINFO_STRUCT (CAPABILITIES, capabilities),
+ FSINFO_STRUCT (SUPPORTS, supports),
+ FSINFO_STRUCT (TIMESTAMP_INFO, timestamp_info),
+ FSINFO_STRING (VOLUME_ID, volume_id),
+ FSINFO_STRUCT (VOLUME_UUID, volume_uuid),
+ FSINFO_STRING (VOLUME_NAME, volume_name),
+ FSINFO_STRING (CELL_NAME, cell_name),
+ FSINFO_STRING (DOMAIN_NAME, domain_name),
+ FSINFO_STRING (REALM_NAME, realm_name),
+ FSINFO_STRING_N (SERVER_NAME, server_name),
+ FSINFO_STRUCT_NM (SERVER_ADDRESS, server_address),
+ FSINFO_STRING_NM (PARAMETER, parameter),
+ FSINFO_STRING_N (SOURCE, source),
+ FSINFO_STRING (NAME_ENCODING, name_encoding),
+ FSINFO_STRING (NAME_CODEPAGE, name_codepage),
+ FSINFO_STRUCT (IO_SIZE, io_size),
+};
+
+#define FSINFO_NAME(X,Y) [FSINFO_ATTR_##X] = #Y
+static const char *fsinfo_attr_names[FSINFO_ATTR__NR] = {
+ FSINFO_NAME (STATFS, statfs),
+ FSINFO_NAME (FSINFO, fsinfo),
+ FSINFO_NAME (IDS, ids),
+ FSINFO_NAME (LIMITS, limits),
+ FSINFO_NAME (CAPABILITIES, capabilities),
+ FSINFO_NAME (SUPPORTS, supports),
+ FSINFO_NAME (TIMESTAMP_INFO, timestamp_info),
+ FSINFO_NAME (VOLUME_ID, volume_id),
+ FSINFO_NAME (VOLUME_UUID, volume_uuid),
+ FSINFO_NAME (VOLUME_NAME, volume_name),
+ FSINFO_NAME (CELL_NAME, cell_name),
+ FSINFO_NAME (DOMAIN_NAME, domain_name),
+ FSINFO_NAME (REALM_NAME, realm_name),
+ FSINFO_NAME (SERVER_NAME, server_name),
+ FSINFO_NAME (SERVER_ADDRESS, server_address),
+ FSINFO_NAME (PARAMETER, parameter),
+ FSINFO_NAME (SOURCE, source),
+ FSINFO_NAME (NAME_ENCODING, name_encoding),
+ FSINFO_NAME (NAME_CODEPAGE, name_codepage),
+ FSINFO_NAME (IO_SIZE, io_size),
+};
+
+union reply {
+ char buffer[4096];
+ struct fsinfo_statfs statfs;
+ struct fsinfo_fsinfo fsinfo;
+ struct fsinfo_ids ids;
+ struct fsinfo_limits limits;
+ struct fsinfo_supports supports;
+ struct fsinfo_capabilities caps;
+ struct fsinfo_timestamp_info timestamps;
+ struct fsinfo_volume_uuid uuid;
+ struct fsinfo_server_address srv_addr;
+ struct fsinfo_io_size io_size;
+};
+
+static void dump_hex(unsigned int *data, int from, int to)
+{
+ unsigned offset, print_offset = 1, col = 0;
+
+ from /= 4;
+ to = (to + 3) / 4;
+
+ for (offset = from; offset < to; offset++) {
+ if (print_offset) {
+ printf("%04x: ", offset * 8);
+ print_offset = 0;
+ }
+ printf("%08x", data[offset]);
+ col++;
+ if ((col & 3) == 0) {
+ printf("\n");
+ print_offset = 1;
+ } else {
+ printf(" ");
+ }
+ }
+
+ if (!print_offset)
+ printf("\n");
+}
+
+static void dump_attr_STATFS(union reply *r, int size)
+{
+ struct fsinfo_statfs *f = &r->statfs;
+
+ printf("\n");
+ printf("\tblocks: n=%llu fr=%llu av=%llu\n",
+ (unsigned long long)f->f_blocks,
+ (unsigned long long)f->f_bfree,
+ (unsigned long long)f->f_bavail);
+
+ printf("\tfiles : n=%llu fr=%llu av=%llu\n",
+ (unsigned long long)f->f_files,
+ (unsigned long long)f->f_ffree,
+ (unsigned long long)f->f_favail);
+ printf("\tbsize : %u\n", f->f_bsize);
+ printf("\tfrsize: %u\n", f->f_frsize);
+}
+
+static void dump_attr_FSINFO(union reply *r, int size)
+{
+ struct fsinfo_fsinfo *f = &r->fsinfo;
+
+ printf("max_attr=%u max_cap=%u\n", f->max_attr, f->max_cap);
+}
+
+static void dump_attr_IDS(union reply *r, int size)
+{
+ struct fsinfo_ids *f = &r->ids;
+
+ printf("\n");
+ printf("\tdev : %02x:%02x\n", f->f_dev_major, f->f_dev_minor);
+ printf("\tfs : type=%x name=%s\n", f->f_fstype, f->f_fs_name);
+ printf("\tflags : %llx\n", (unsigned long long)f->f_flags);
+ printf("\tfsid : %llx\n", (unsigned long long)f->f_fsid);
+}
+
+static void dump_attr_LIMITS(union reply *r, int size)
+{
+ struct fsinfo_limits *f = &r->limits;
+
+ printf("\n");
+ printf("\tmax file size: %llx\n", f->max_file_size);
+ printf("\tmax ids : u=%llx g=%llx p=%llx\n",
+ f->max_uid, f->max_gid, f->max_projid);
+ printf("\tmax dev : maj=%x min=%x\n",
+ f->max_dev_major, f->max_dev_minor);
+ printf("\tmax links : %x\n", f->max_hard_links);
+ printf("\tmax xattr : n=%x b=%x\n",
+ f->max_xattr_name_len, f->max_xattr_body_len);
+ printf("\tmax len : file=%x sym=%x\n",
+ f->max_filename_len, f->max_symlink_len);
+}
+
+static void dump_attr_SUPPORTS(union reply *r, int size)
+{
+ struct fsinfo_supports *f = &r->supports;
+
+ printf("\n");
+ printf("\tstx_attr=%llx\n", f->stx_attributes);
+ printf("\tstx_mask=%x\n", f->stx_mask);
+ printf("\tioc_flags=%x\n", f->ioc_flags);
+ printf("\twin_fattrs=%x\n", f->win_file_attrs);
+}
+
+#define FSINFO_CAP_NAME(C) [FSINFO_CAP_##C] = #C
+static const char *fsinfo_cap_names[FSINFO_CAP__NR] = {
+ FSINFO_CAP_NAME(IS_KERNEL_FS),
+ FSINFO_CAP_NAME(IS_BLOCK_FS),
+ FSINFO_CAP_NAME(IS_FLASH_FS),
+ FSINFO_CAP_NAME(IS_NETWORK_FS),
+ FSINFO_CAP_NAME(IS_AUTOMOUNTER_FS),
+ FSINFO_CAP_NAME(AUTOMOUNTS),
+ FSINFO_CAP_NAME(ADV_LOCKS),
+ FSINFO_CAP_NAME(MAND_LOCKS),
+ FSINFO_CAP_NAME(LEASES),
+ FSINFO_CAP_NAME(UIDS),
+ FSINFO_CAP_NAME(GIDS),
+ FSINFO_CAP_NAME(PROJIDS),
+ FSINFO_CAP_NAME(ID_NAMES),
+ FSINFO_CAP_NAME(ID_GUIDS),
+ FSINFO_CAP_NAME(WINDOWS_ATTRS),
+ FSINFO_CAP_NAME(USER_QUOTAS),
+ FSINFO_CAP_NAME(GROUP_QUOTAS),
+ FSINFO_CAP_NAME(PROJECT_QUOTAS),
+ FSINFO_CAP_NAME(XATTRS),
+ FSINFO_CAP_NAME(JOURNAL),
+ FSINFO_CAP_NAME(DATA_IS_JOURNALLED),
+ FSINFO_CAP_NAME(O_SYNC),
+ FSINFO_CAP_NAME(O_DIRECT),
+ FSINFO_CAP_NAME(VOLUME_ID),
+ FSINFO_CAP_NAME(VOLUME_UUID),
+ FSINFO_CAP_NAME(VOLUME_NAME),
+ FSINFO_CAP_NAME(VOLUME_FSID),
+ FSINFO_CAP_NAME(CELL_NAME),
+ FSINFO_CAP_NAME(DOMAIN_NAME),
+ FSINFO_CAP_NAME(REALM_NAME),
+ FSINFO_CAP_NAME(IVER_ALL_CHANGE),
+ FSINFO_CAP_NAME(IVER_DATA_CHANGE),
+ FSINFO_CAP_NAME(IVER_MONO_INCR),
+ FSINFO_CAP_NAME(SYMLINKS),
+ FSINFO_CAP_NAME(HARD_LINKS),
+ FSINFO_CAP_NAME(HARD_LINKS_1DIR),
+ FSINFO_CAP_NAME(DEVICE_FILES),
+ FSINFO_CAP_NAME(UNIX_SPECIALS),
+ FSINFO_CAP_NAME(RESOURCE_FORKS),
+ FSINFO_CAP_NAME(NAME_CASE_INDEP),
+ FSINFO_CAP_NAME(NAME_NON_UTF8),
+ FSINFO_CAP_NAME(NAME_HAS_CODEPAGE),
+ FSINFO_CAP_NAME(SPARSE),
+ FSINFO_CAP_NAME(NOT_PERSISTENT),
+ FSINFO_CAP_NAME(NO_UNIX_MODE),
+ FSINFO_CAP_NAME(HAS_ATIME),
+ FSINFO_CAP_NAME(HAS_BTIME),
+ FSINFO_CAP_NAME(HAS_CTIME),
+ FSINFO_CAP_NAME(HAS_MTIME),
+};
+
+static void dump_attr_CAPABILITIES(union reply *r, int size)
+{
+ struct fsinfo_capabilities *f = &r->caps;
+ int i;
+
+ for (i = 0; i < sizeof(f->capabilities); i++)
+ printf("%02x", f->capabilities[i]);
+ printf("\n");
+ for (i = 0; i < FSINFO_CAP__NR; i++)
+ if (f->capabilities[i / 8] & (1 << (i % 8)))
+ printf("\t- %s\n", fsinfo_cap_names[i]);
+}
+
+static void dump_attr_TIMESTAMP_INFO(union reply *r, int size)
+{
+ struct fsinfo_timestamp_info *f = &r->timestamps;
+
+ printf("range=%llx-%llx\n",
+ (unsigned long long)f->minimum_timestamp,
+ (unsigned long long)f->maximum_timestamp);
+
+#define print_time(G) \
+ printf("\t"#G"time : gran=%gs\n", \
+ (f->G##time_gran_mantissa * \
+ pow(10., f->G##time_gran_exponent)))
+ print_time(a);
+ print_time(b);
+ print_time(c);
+ print_time(m);
+}
+
+static void dump_attr_VOLUME_UUID(union reply *r, int size)
+{
+ struct fsinfo_volume_uuid *f = &r->uuid;
+
+ printf("%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x"
+ "-%02x%02x%02x%02x%02x%02x\n",
+ f->uuid[ 0], f->uuid[ 1],
+ f->uuid[ 2], f->uuid[ 3],
+ f->uuid[ 4], f->uuid[ 5],
+ f->uuid[ 6], f->uuid[ 7],
+ f->uuid[ 8], f->uuid[ 9],
+ f->uuid[10], f->uuid[11],
+ f->uuid[12], f->uuid[13],
+ f->uuid[14], f->uuid[15]);
+}
+
+static void dump_attr_SERVER_ADDRESS(union reply *r, int size)
+{
+ struct fsinfo_server_address *f = &r->srv_addr;
+
+ printf("family=%u\n", f->address.ss_family);
+}
+
+static void dump_attr_IO_SIZE(union reply *r, int size)
+{
+ struct fsinfo_io_size *f = &r->io_size;
+
+ printf("dio_size=%u\n", f->dio_size_gran);
+}
+
+/*
+ *
+ */
+typedef void (*dumper_t)(union reply *r, int size);
+
+#define FSINFO_DUMPER(N) [FSINFO_ATTR_##N] = dump_attr_##N
+static const dumper_t fsinfo_attr_dumper[FSINFO_ATTR__NR] = {
+ FSINFO_DUMPER(STATFS),
+ FSINFO_DUMPER(FSINFO),
+ FSINFO_DUMPER(IDS),
+ FSINFO_DUMPER(LIMITS),
+ FSINFO_DUMPER(SUPPORTS),
+ FSINFO_DUMPER(CAPABILITIES),
+ FSINFO_DUMPER(TIMESTAMP_INFO),
+ FSINFO_DUMPER(VOLUME_UUID),
+ FSINFO_DUMPER(SERVER_ADDRESS),
+ FSINFO_DUMPER(IO_SIZE),
+};
+
+static void dump_fsinfo(enum fsinfo_attribute attr, __u8 about,
+ union reply *r, int size)
+{
+ dumper_t dumper = fsinfo_attr_dumper[attr];
+ unsigned int len;
+
+ if (!dumper) {
+ printf("<no dumper>\n");
+ return;
+ }
+
+ len = about & 0x3fff;
+ if (size < len) {
+ printf("<short data %u/%u>\n", size, len);
+ return;
+ }
+
+ dumper(r, size);
+}
+
+/*
+ * Try one subinstance of an attribute.
+ */
+static int try_one(const char *file, struct fsinfo_params *params, bool raw)
+{
+ union reply r;
+ char *p;
+ int ret;
+ __u16 about;
+
+ memset(&r.buffer, 0xbd, sizeof(r.buffer));
+
+ errno = 0;
+ ret = fsinfo(AT_FDCWD, file, params, r.buffer, sizeof(r.buffer));
+ if (params->request >= FSINFO_ATTR__NR) {
+ if (ret == -1 && errno == EOPNOTSUPP)
+ exit(0);
+ fprintf(stderr, "Unexpected error for too-large command %u: %m\n",
+ params->request);
+ exit(1);
+ }
+
+ if (debug)
+ printf("fsinfo(%s,%s,%u,%u) = %d: %m\n",
+ file, fsinfo_attr_names[params->request],
+ params->Nth, params->Mth, ret);
+
+ about = fsinfo_buffer_sizes[params->request];
+ if (ret == -1) {
+ if (errno == ENODATA) {
+ switch (about & 0xc000) {
+ case 0x0000:
+ if (params->Nth == 0 && params->Mth == 0) {
+ fprintf(stderr,
+ "Unexpected ENODATA1 (%u[%u][%u])\n",
+ params->request, params->Nth, params->Mth);
+ exit(1);
+ }
+ break;
+ case 0x4000:
+ if (params->Nth == 0 && params->Mth == 0) {
+ fprintf(stderr,
+ "Unexpected ENODATA2 (%u[%u][%u])\n",
+ params->request, params->Nth, params->Mth);
+ exit(1);
+ }
+ break;
+ }
+ return (params->Mth == 0) ? 2 : 1;
+ }
+ if (errno == EOPNOTSUPP) {
+ if (params->Nth > 0 || params->Mth > 0) {
+ fprintf(stderr,
+ "Should return -ENODATA (%u[%u][%u])\n",
+ params->request, params->Nth, params->Mth);
+ exit(1);
+ }
+ //printf("\e[33m%s\e[m: <not supported>\n",
+ // fsinfo_attr_names[attr]);
+ return 2;
+ }
+ perror(file);
+ exit(1);
+ }
+
+ if (raw) {
+ if (ret > 4096)
+ ret = 4096;
+ dump_hex((unsigned int *)&r.buffer, 0, ret);
+ return 0;
+ }
+
+ switch (about & 0xc000) {
+ case 0x0000:
+ printf("\e[33m%s\e[m: ",
+ fsinfo_attr_names[params->request]);
+ break;
+ case 0x4000:
+ printf("\e[33m%s[%u]\e[m: ",
+ fsinfo_attr_names[params->request],
+ params->Nth);
+ break;
+ case 0x8000:
+ printf("\e[33m%s[%u][%u]\e[m: ",
+ fsinfo_attr_names[params->request],
+ params->Nth, params->Mth);
+ break;
+ }
+
+ switch (about) {
+ /* Struct */
+ case 0x0001 ... 0x3fff:
+ case 0x4001 ... 0x7fff:
+ case 0x8001 ... 0xbfff:
+ dump_fsinfo(params->request, about, &r, ret);
+ return 0;
+
+ /* String */
+ case 0x0000:
+ case 0x4000:
+ case 0x8000:
+ if (ret >= 4096) {
+ ret = 4096;
+ r.buffer[4092] = '.';
+ r.buffer[4093] = '.';
+ r.buffer[4094] = '.';
+ r.buffer[4095] = 0;
+ } else {
+ r.buffer[ret] = 0;
+ }
+ for (p = r.buffer; *p; p++) {
+ if (!isprint(*p)) {
+ printf("<non-printable>\n");
+ continue;
+ }
+ }
+ printf("%s\n", r.buffer);
+ return 0;
+
+ default:
+ fprintf(stderr, "Fishy about %u %02x\n", params->request, about);
+ exit(1);
+ }
+}
+
+/*
+ *
+ */
+int main(int argc, char **argv)
+{
+ struct fsinfo_params params = {
+ .at_flags = AT_SYMLINK_NOFOLLOW,
+ };
+ unsigned int attr;
+ int raw = 0, opt, Nth, Mth;
+
+ while ((opt = getopt(argc, argv, "adlr"))) {
+ switch (opt) {
+ case 'a':
+ params.at_flags |= AT_NO_AUTOMOUNT;
+ continue;
+ case 'd':
+ debug = true;
+ continue;
+ case 'l':
+ params.at_flags &= ~AT_SYMLINK_NOFOLLOW;
+ continue;
+ case 'r':
+ raw = 1;
+ continue;
+ }
+ break;
+ }
+
+ argc -= optind;
+ argv += optind;
+
+ if (argc != 1) {
+ printf("Format: test-fsinfo [-alr] <file>\n");
+ exit(2);
+ }
+
+ for (attr = 0; attr <= FSINFO_ATTR__NR; attr++) {
+ Nth = 0;
+ do {
+ Mth = 0;
+ do {
+ params.request = attr;
+ params.Nth = Nth;
+ params.Mth = Mth;
+
+ switch (try_one(argv[0], ¶ms, raw)) {
+ case 0:
+ continue;
+ case 1:
+ goto done_M;
+ case 2:
+ goto done_N;
+ }
+ } while (++Mth < 100);
+
+ done_M:
+ if (Mth >= 100) {
+ fprintf(stderr, "Fishy: Mth == %u\n", Mth);
+ break;
+ }
+
+ } while (++Nth < 100);
+
+ done_N:
+ if (Nth >= 100) {
+ fprintf(stderr, "Fishy: Nth == %u\n", Nth);
+ break;
+ }
+ }
+
+ return 0;
+}
^ permalink raw reply related [flat|nested] 8+ messages in thread* [PATCH 4/5] vfs: Allow fsinfo() to be used to query an fs parameter description
2018-08-01 16:13 [PATCH 0/5] VFS: Introduce filesystem information query syscall David Howells
` (2 preceding siblings ...)
2018-08-01 16:14 ` [PATCH 3/5] vfs: Allow fsinfo() to query what's in an fs_context David Howells
@ 2018-08-01 16:14 ` David Howells
2018-08-01 16:14 ` [PATCH 5/5] vfs: Implement parameter value retrieval with fsinfo() David Howells
4 siblings, 0 replies; 8+ messages in thread
From: David Howells @ 2018-08-01 16:14 UTC (permalink / raw)
To: viro; +Cc: torvalds, dhowells, linux-fsdevel, linux-kernel
Provide fsinfo() attributes that can be used to query a filesystem
parameter description. To do this, fsinfo() can be called on an
fs_context that doesn't yet have a superblock created and attached.
It can be obtained by doing, for example:
fd = fsopen("ext4", 0);
struct fsinfo_param_name name;
struct fsinfo_params params = {
.request = fsinfo_attr_param_name,
.Nth = 3,
};
fsinfo(fd, NULL, ¶ms, &name, sizeof(name));
to query the 4th parameter name in the name to parameter ID mapping table.
Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/statfs.c | 85 +++++++++++++++++++++++++
include/uapi/linux/fsinfo.h | 67 ++++++++++++++++++++
samples/statx/Makefile | 4 +
samples/statx/test-fs-query.c | 137 +++++++++++++++++++++++++++++++++++++++++
samples/statx/test-fsinfo.c | 8 ++
5 files changed, 299 insertions(+), 2 deletions(-)
create mode 100644 samples/statx/test-fs-query.c
diff --git a/fs/statfs.c b/fs/statfs.c
index 2757fbaa80fb..567bf48c38e6 100644
--- a/fs/statfs.c
+++ b/fs/statfs.c
@@ -10,6 +10,7 @@
#include <linux/uaccess.h>
#include <linux/compat.h>
#include <linux/fsinfo.h>
+#include <linux/fs_parser.h>
#include "internal.h"
static int flags_by_mnt(int mnt_flags)
@@ -568,12 +569,72 @@ static int fsinfo_generic_io_size(struct dentry *dentry,
return sizeof(*c);
}
+static int fsinfo_generic_param_description(struct file_system_type *f,
+ struct fsinfo_kparams *params)
+{
+ const struct fs_parameter_description *desc = f->parameters;
+ struct fsinfo_param_description *p = params->buffer;
+
+ if (!desc)
+ return -ENODATA;
+
+ p->nr_params = desc->nr_params;
+ p->nr_names = desc->nr_keys;
+ p->nr_enum_names = desc->nr_enums;
+ return sizeof(*p);
+}
+
+static int fsinfo_generic_param_specification(struct file_system_type *f,
+ struct fsinfo_kparams *params)
+{
+ const struct fs_parameter_description *desc = f->parameters;
+ struct fsinfo_param_specification *p = params->buffer;
+
+ if (!desc || !desc->specs || params->Nth >= desc->nr_params)
+ return -ENODATA;
+
+ p->type = desc->specs[params->Nth].type;
+ p->flags = desc->specs[params->Nth].flags;
+ return sizeof(*p);
+}
+
+static int fsinfo_generic_param_name(struct file_system_type *f,
+ struct fsinfo_kparams *params)
+{
+ const struct fs_parameter_description *desc = f->parameters;
+ struct fsinfo_param_name *p = params->buffer;
+
+ if (!desc || !desc->keys || params->Nth >= desc->nr_keys)
+ return -ENODATA;
+
+ p->param_index = desc->keys[params->Nth].value;
+ strcpy(p->name, desc->keys[params->Nth].name);
+ return sizeof(*p);
+}
+
+static int fsinfo_generic_param_enum(struct file_system_type *f,
+ struct fsinfo_kparams *params)
+{
+ const struct fs_parameter_description *desc = f->parameters;
+ struct fsinfo_param_enum *p = params->buffer;
+
+ if (!desc || !desc->enums || params->Nth >= desc->nr_enums)
+ return -ENODATA;
+
+ p->param_index = desc->enums[params->Nth].param_id;
+ strcpy(p->name, desc->enums[params->Nth].name);
+ return sizeof(*p);
+}
+
/*
* Implement some queries generically from stuff in the superblock.
*/
int generic_fsinfo(struct dentry *dentry, struct fsinfo_kparams *params)
{
+ struct file_system_type *f = dentry->d_sb->s_type;
+
#define _gen(X, Y) FSINFO_ATTR_##X: return fsinfo_generic_##Y(dentry, params->buffer)
+#define _genf(X, Y) FSINFO_ATTR_##X: return fsinfo_generic_##Y(f, params)
switch (params->request) {
case _gen(STATFS, statfs);
@@ -586,6 +647,10 @@ int generic_fsinfo(struct dentry *dentry, struct fsinfo_kparams *params)
case _gen(VOLUME_ID, volume_id);
case _gen(NAME_ENCODING, name_encoding);
case _gen(IO_SIZE, io_size);
+ case _genf(PARAM_DESCRIPTION, param_description);
+ case _genf(PARAM_SPECIFICATION, param_specification);
+ case _genf(PARAM_NAME, param_name);
+ case _genf(PARAM_ENUM, param_enum);
default:
return -EOPNOTSUPP;
}
@@ -626,7 +691,8 @@ int vfs_fsinfo(const struct path *path, struct fsinfo_kparams *params)
return ret;
if (params->request == FSINFO_ATTR_IDS &&
- params->buffer) {
+ params->buffer &&
+ path->mnt) {
struct fsinfo_ids *p = params->buffer;
p->f_flags |= flags_by_mnt(path->mnt->mnt_flags);
@@ -670,11 +736,24 @@ static int vfs_fsinfo_path(int dfd, const char __user *filename,
static int vfs_fsinfo_fscontext(struct fs_context *fc,
struct fsinfo_kparams *params)
{
+ struct file_system_type *f = fc->fs_type;
int ret;
if (fc->ops == &legacy_fs_context_ops)
return -EOPNOTSUPP;
+ /* Filesystem parameter query is static information and doesn't need a
+ * lock to read it.
+ */
+ switch (params->request) {
+ case _genf(PARAM_DESCRIPTION, param_description);
+ case _genf(PARAM_SPECIFICATION, param_specification);
+ case _genf(PARAM_NAME, param_name);
+ case _genf(PARAM_ENUM, param_enum);
+ default:
+ break;
+ }
+
ret = mutex_lock_interruptible(&fc->uapi_mutex);
if (ret < 0)
return ret;
@@ -749,6 +828,10 @@ static const u16 fsinfo_buffer_sizes[FSINFO_ATTR__NR] = {
FSINFO_STRING (NAME_ENCODING, name_encoding),
FSINFO_STRING (NAME_CODEPAGE, name_codepage),
FSINFO_STRUCT (IO_SIZE, io_size),
+ FSINFO_STRUCT (PARAM_DESCRIPTION, param_description),
+ FSINFO_STRUCT_N (PARAM_SPECIFICATION, param_specification),
+ FSINFO_STRUCT_N (PARAM_NAME, param_name),
+ FSINFO_STRUCT_N (PARAM_ENUM, param_enum),
};
/**
diff --git a/include/uapi/linux/fsinfo.h b/include/uapi/linux/fsinfo.h
index ca82cfb5f38a..73dea8e7a68d 100644
--- a/include/uapi/linux/fsinfo.h
+++ b/include/uapi/linux/fsinfo.h
@@ -35,6 +35,10 @@ enum fsinfo_attribute {
FSINFO_ATTR_NAME_ENCODING = 17, /* Filename encoding (string) */
FSINFO_ATTR_NAME_CODEPAGE = 18, /* Filename codepage (string) */
FSINFO_ATTR_IO_SIZE = 19, /* Optimal I/O sizes */
+ FSINFO_ATTR_PARAM_DESCRIPTION = 20, /* General fs parameter description */
+ FSINFO_ATTR_PARAM_SPECIFICATION = 21, /* Nth parameter specification */
+ FSINFO_ATTR_PARAM_NAME = 22, /* Nth name to param index */
+ FSINFO_ATTR_PARAM_ENUM = 23, /* Nth enum-to-val */
FSINFO_ATTR__NR
};
@@ -232,4 +236,67 @@ struct fsinfo_fsinfo {
__u32 max_cap; /* Number of supported capabilities (fsinfo_cap__nr) */
};
+/*
+ * Information struct for fsinfo(fsinfo_attr_param_description).
+ *
+ * Query the parameter set for a filesystem.
+ */
+struct fsinfo_param_description {
+ __u32 nr_params; /* Number of individual parameters */
+ __u32 nr_names; /* Number of parameter names */
+ __u32 nr_enum_names; /* Number of enum names */
+};
+
+/*
+ * Information struct for fsinfo(fsinfo_attr_param_specification).
+ *
+ * Query the specification of the Nth filesystem parameter.
+ */
+struct fsinfo_param_specification {
+ __u32 type; /* enum fsinfo_param_specification_type */
+ __u32 flags; /* Qualifiers */
+};
+
+enum fsinfo_param_specification_type {
+ FSINFO_PARAM_SPEC_NOT_DEFINED,
+ FSINFO_PARAM_SPEC_TAKES_NO_VALUE,
+ FSINFO_PARAM_SPEC_IS_BOOL,
+ FSINFO_PARAM_SPEC_IS_U32,
+ FSINFO_PARAM_SPEC_IS_U32_OCTAL,
+ FSINFO_PARAM_SPEC_IS_U32_HEX,
+ FSINFO_PARAM_SPEC_IS_S32,
+ FSINFO_PARAM_SPEC_IS_ENUM,
+ FSINFO_PARAM_SPEC_IS_STRING,
+ FSINFO_PARAM_SPEC_IS_BLOB,
+ FSINFO_PARAM_SPEC_IS_BLOCKDEV,
+ FSINFO_PARAM_SPEC_IS_PATH,
+ FSINFO_PARAM_SPEC_IS_FD,
+ NR__FSINFO_PARAM_SPEC
+};
+
+#define FSINFO_PARAM_SPEC_VALUE_IS_OPTIONAL 0X00000001
+#define FSINFO_PARAM_SPEC_PREFIX_NO_IS_NEG 0X00000002
+#define FSINFO_PARAM_SPEC_EMPTY_STRING_IS_NEG 0X00000004
+#define FSINFO_PARAM_SPEC_DEPRECATED 0X00000008
+
+/*
+ * Information struct for fsinfo(fsinfo_attr_param_name).
+ *
+ * Query the Nth filesystem parameter name
+ */
+struct fsinfo_param_name {
+ __u32 param_index; /* Index of the parameter specification */
+ char name[252]; /* Name of the parameter */
+};
+
+/*
+ * Information struct for fsinfo(fsinfo_attr_param_enum).
+ *
+ * Query the Nth filesystem enum parameter value name.
+ */
+struct fsinfo_param_enum {
+ __u32 param_index; /* Index of the relevant parameter specification */
+ char name[252]; /* Name of the enum value */
+};
+
#endif /* _UAPI_LINUX_FSINFO_H */
diff --git a/samples/statx/Makefile b/samples/statx/Makefile
index 9cb9a88e3a10..05b4d30cdd3c 100644
--- a/samples/statx/Makefile
+++ b/samples/statx/Makefile
@@ -1,5 +1,5 @@
# List of programs to build
-hostprogs-$(CONFIG_SAMPLE_STATX) := test-statx test-fsinfo
+hostprogs-$(CONFIG_SAMPLE_STATX) := test-statx test-fsinfo test-fs-query
# Tell kbuild to always build the programs
always := $(hostprogs-y)
@@ -8,3 +8,5 @@ HOSTCFLAGS_test-statx.o += -I$(objtree)/usr/include
HOSTCFLAGS_test-fsinfo.o += -I$(objtree)/usr/include
HOSTLOADLIBES_test-fsinfo += -lm
+
+HOSTCFLAGS_test-fs-query.o += -I$(objtree)/usr/include
diff --git a/samples/statx/test-fs-query.c b/samples/statx/test-fs-query.c
new file mode 100644
index 000000000000..25c69d0df084
--- /dev/null
+++ b/samples/statx/test-fs-query.c
@@ -0,0 +1,137 @@
+/* Test using the fsinfo() system call to query mount parameters.
+ *
+ * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#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 <fcntl.h>
+#include <sys/syscall.h>
+#include <linux/fsinfo.h>
+#include <linux/socket.h>
+#include <sys/stat.h>
+
+static int fsopen(const char *fs_name, unsigned int flags)
+{
+ return syscall(__NR_fsopen, fs_name, flags);
+}
+
+static ssize_t fsinfo(int dfd, const char *filename, struct fsinfo_params *params,
+ void *buffer, size_t buf_size)
+{
+ return syscall(__NR_fsinfo, dfd, filename, params, buffer, buf_size);
+}
+
+static const char *param_types[NR__FSINFO_PARAM_SPEC] = {
+ [FSINFO_PARAM_SPEC_NOT_DEFINED] = "?undef",
+ [FSINFO_PARAM_SPEC_TAKES_NO_VALUE] = "no-val",
+ [FSINFO_PARAM_SPEC_IS_BOOL] = "bool",
+ [FSINFO_PARAM_SPEC_IS_U32] = "u32",
+ [FSINFO_PARAM_SPEC_IS_U32_OCTAL] = "octal",
+ [FSINFO_PARAM_SPEC_IS_U32_HEX] = "hex",
+ [FSINFO_PARAM_SPEC_IS_S32] = "s32",
+ [FSINFO_PARAM_SPEC_IS_ENUM] = "enum",
+ [FSINFO_PARAM_SPEC_IS_STRING] = "string",
+ [FSINFO_PARAM_SPEC_IS_BLOB] = "binary",
+ [FSINFO_PARAM_SPEC_IS_BLOCKDEV] = "blockdev",
+ [FSINFO_PARAM_SPEC_IS_PATH] = "path",
+ [FSINFO_PARAM_SPEC_IS_FD] = "fd",
+};
+
+/*
+ *
+ */
+int main(int argc, char **argv)
+{
+ struct fsinfo_param_description desc;
+ struct fsinfo_param_specification spec;
+ struct fsinfo_param_name name;
+ struct fsinfo_param_enum enum_name;
+
+ struct fsinfo_params params = {
+ .at_flags = AT_SYMLINK_NOFOLLOW,
+ };
+ int fd;
+
+ if (argc != 2) {
+ printf("Format: test-fs-query <fs_name>\n");
+ exit(2);
+ }
+
+ fd = fsopen(argv[1], 0);
+ if (fd == -1) {
+ perror(argv[1]);
+ exit(1);
+ }
+
+ params.request = FSINFO_ATTR_PARAM_DESCRIPTION;
+ if (fsinfo(fd, NULL, ¶ms, &desc, sizeof(desc)) == -1) {
+ perror("fsinfo/desc");
+ exit(1);
+ }
+
+ printf("Filesystem %s has %u parameters\n", argv[1], desc.nr_params);
+
+ params.request = FSINFO_ATTR_PARAM_SPECIFICATION;
+ for (params.Nth = 0; params.Nth < desc.nr_params; params.Nth++) {
+ if (fsinfo(fd, NULL, ¶ms, &spec, sizeof(spec)) == -1) {
+ if (errno == ENODATA)
+ break;
+ perror("fsinfo/spec");
+ exit(1);
+ }
+ printf("- PARAM[%3u] type=%u(%s)%s%s%s%s\n",
+ params.Nth,
+ spec.type,
+ spec.type < NR__FSINFO_PARAM_SPEC ? param_types[spec.type] : "?type",
+ spec.flags & FSINFO_PARAM_SPEC_VALUE_IS_OPTIONAL ? " -opt" : "",
+ spec.flags & FSINFO_PARAM_SPEC_PREFIX_NO_IS_NEG ? " -neg-no" : "",
+ spec.flags & FSINFO_PARAM_SPEC_EMPTY_STRING_IS_NEG ? " -neg-empty" : "",
+ spec.flags & FSINFO_PARAM_SPEC_DEPRECATED ? " -dep" : "");
+ }
+
+ printf("Filesystem has %u parameter names\n", desc.nr_names);
+
+ params.request = FSINFO_ATTR_PARAM_NAME;
+ for (params.Nth = 0; params.Nth < desc.nr_names; params.Nth++) {
+ if (fsinfo(fd, NULL, ¶ms, &name, sizeof(name)) == -1) {
+ if (errno == ENODATA)
+ break;
+ perror("fsinfo/name");
+ exit(1);
+ }
+ printf("- NAME[%3u] %s -> %u\n",
+ params.Nth, name.name, name.param_index);
+ }
+
+ printf("Filesystem has %u enumeration values\n", desc.nr_enum_names);
+
+ params.request = FSINFO_ATTR_PARAM_ENUM;
+ for (params.Nth = 0; params.Nth < desc.nr_enum_names; params.Nth++) {
+ if (fsinfo(fd, NULL, ¶ms, &enum_name, sizeof(enum_name)) == -1) {
+ if (errno == ENODATA)
+ break;
+ perror("fsinfo/enum");
+ exit(1);
+ }
+ printf("- ENUM[%3u] %3u.%s\n",
+ params.Nth, enum_name.param_index, enum_name.name);
+ }
+ return 0;
+}
diff --git a/samples/statx/test-fsinfo.c b/samples/statx/test-fsinfo.c
index 5fb3dcccff26..21714ef7ef5b 100644
--- a/samples/statx/test-fsinfo.c
+++ b/samples/statx/test-fsinfo.c
@@ -63,6 +63,10 @@ static const __u16 fsinfo_buffer_sizes[FSINFO_ATTR__NR] = {
FSINFO_STRING (NAME_ENCODING, name_encoding),
FSINFO_STRING (NAME_CODEPAGE, name_codepage),
FSINFO_STRUCT (IO_SIZE, io_size),
+ FSINFO_STRUCT (PARAM_DESCRIPTION, param_description),
+ FSINFO_STRUCT_N (PARAM_SPECIFICATION, param_specification),
+ FSINFO_STRUCT_N (PARAM_NAME, param_name),
+ FSINFO_STRUCT_N (PARAM_ENUM, param_enum),
};
#define FSINFO_NAME(X,Y) [FSINFO_ATTR_##X] = #Y
@@ -87,6 +91,10 @@ static const char *fsinfo_attr_names[FSINFO_ATTR__NR] = {
FSINFO_NAME (NAME_ENCODING, name_encoding),
FSINFO_NAME (NAME_CODEPAGE, name_codepage),
FSINFO_NAME (IO_SIZE, io_size),
+ FSINFO_NAME (PARAM_DESCRIPTION, param_description),
+ FSINFO_NAME (PARAM_SPECIFICATION, param_specification),
+ FSINFO_NAME (PARAM_NAME, param_name),
+ FSINFO_NAME (PARAM_ENUM, param_enum),
};
union reply {
^ permalink raw reply related [flat|nested] 8+ messages in thread* [PATCH 5/5] vfs: Implement parameter value retrieval with fsinfo()
2018-08-01 16:13 [PATCH 0/5] VFS: Introduce filesystem information query syscall David Howells
` (3 preceding siblings ...)
2018-08-01 16:14 ` [PATCH 4/5] vfs: Allow fsinfo() to be used to query an fs parameter description David Howells
@ 2018-08-01 16:14 ` David Howells
4 siblings, 0 replies; 8+ messages in thread
From: David Howells @ 2018-08-01 16:14 UTC (permalink / raw)
To: viro; +Cc: torvalds, dhowells, linux-fsdevel, linux-kernel
Implement parameter value retrieval with fsinfo() - akin to parsing
/proc/mounts.
This allows the values of each parameter to be retrieved in an order
corresponding to the Nth index used by FSINFO_ATTR_PARAM_SPECIFICATION. If
a parameter isn't set, an empty string is returned. Parameters may have
multiple values, which can be accessed using the Mth index. For example,
set:
struct fsinfo_params params = {
.request = FSINFO_ATTR_PARAM_SPECIFICATION,
.Nth = 3,
};
this can be passed to fsinfo() to retrieve the type information for the
parameter #3. Value #2 of parameter #3 can then be retrieved using:
struct fsinfo_params params = {
.request = FSINFO_ATTR_PARAM_SPECIFICATION,
.Nth = 3,
.Mth = 2,
};
fsinfo() returned -ENODATA if Nth is beyond the last parameter or Mth is
beyond the last value of that parameter.
Note that it is permissible for the filesystem to add extra values on the
end beyond the number of specs returned by FSINFO_ATTR_PARAM_SPECIFICATION.
This is used by cgroup-v1 to list the supported subsystem names after the
standard parameters.
Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/afs/internal.h | 1 +
fs/afs/super.c | 39 +++++++++++++++++++++++-
fs/hugetlbfs/inode.c | 65 +++++++++++++++++++++++++++++++++++++++++
fs/kernfs/mount.c | 16 ++++++++++
include/linux/kernfs.h | 2 +
kernel/cgroup/cgroup-v1.c | 72 +++++++++++++++++++++++++++++++++++++++++++++
kernel/cgroup/cgroup.c | 31 +++++++++++++++++++
samples/Kconfig | 2 +
8 files changed, 225 insertions(+), 3 deletions(-)
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index e35d59761d47..35aa4bd79145 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -195,6 +195,7 @@ struct afs_super_info {
struct afs_cell *cell; /* The cell in which the volume resides */
struct afs_volume *volume; /* volume record */
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 10b5616a7843..7c97836e7937 100644
--- a/fs/afs/super.c
+++ b/fs/afs/super.c
@@ -197,7 +197,7 @@ 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");
return 0;
}
@@ -444,7 +444,7 @@ 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;
@@ -483,6 +483,8 @@ static struct afs_super_info *afs_alloc_sbi(struct fs_context *fc)
as->cell = afs_get_cell(ctx->cell);
as->volume = __afs_get_volume(ctx->volume);
}
+ if (ctx->autocell)
+ as->autocell = true;
}
return as;
}
@@ -789,6 +791,7 @@ static int afs_get_fsinfo(struct dentry *dentry, struct fsinfo_kparams *params)
struct afs_volume *volume = as->volume;
struct afs_cell *cell = as->cell;
struct afs_net *net = afs_d2net(dentry);
+ const char *str = NULL;
bool dyn_root = as->dyn_root;
int ret;
@@ -893,7 +896,39 @@ static int afs_get_fsinfo(struct dentry *dentry, struct fsinfo_kparams *params)
afs_put_serverlist(net, slist);
return ret;
+ case FSINFO_ATTR_PARAMETER:
+ if (params->Mth)
+ return -ENODATA;
+ switch (params->Nth) {
+ case Opt_autocell:
+ if (as->autocell)
+ str = "autocell";
+ goto string;
+ case Opt_dyn:
+ if (dyn_root)
+ str = "dyn";
+ goto string;
+ case Opt_source:
+ if (dyn_root)
+ return 0;
+ return sprintf(params->buffer, "source=%c%s:%s%s",
+ volume->type == AFSVL_RWVOL ? '%' : '#',
+ cell->name,
+ volume->name,
+ volume->type == AFSVL_RWVOL ? "" :
+ volume->type == AFSVL_ROVOL ? ".readonly" :
+ ".backup");
+ default:
+ return -ENODATA;
+ }
+
default:
return generic_fsinfo(dentry, params);
}
+
+string:
+ if (!str)
+ return 0;
+ strcpy(params->buffer, str);
+ return strlen(params->buffer);
}
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 28f6c28e55dc..e2378c8ce7e0 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -28,6 +28,7 @@
#include <linux/hugetlb.h>
#include <linux/pagevec.h>
#include <linux/fs_parser.h>
+#include <linux/fsinfo.h>
#include <linux/mman.h>
#include <linux/slab.h>
#include <linux/dnotify.h>
@@ -948,6 +949,69 @@ static int hugetlbfs_show_options(struct seq_file *m, struct dentry *root)
return 0;
}
+static int hugetlbfs_get_fsinfo(struct dentry *dentry, struct fsinfo_kparams *params)
+{
+ struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
+ struct hugepage_subpool *spool = sbinfo->spool;
+ unsigned long hpage_size = huge_page_size(sbinfo->hstate);
+ unsigned hpage_shift = huge_page_shift(sbinfo->hstate);
+ char mod;
+
+ switch (params->request) {
+ case FSINFO_ATTR_PARAMETER:
+ if (params->Mth)
+ return -ENODATA;
+ switch (params->Nth) {
+ case Opt_uid:
+ if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID))
+ return sprintf(params->buffer, "uid=%u",
+ from_kuid_munged(&init_user_ns,
+ sbinfo->uid));
+ return 0;
+ case Opt_gid:
+ if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID))
+ return sprintf(params->buffer, "gid=%u",
+ from_kgid_munged(&init_user_ns,
+ sbinfo->gid));
+ return 0;
+
+ case Opt_size:
+ if (!spool || spool->max_hpages == -1)
+ return 0;
+ return sprintf(params->buffer, "size=%llu",
+ (unsigned long long)spool->max_hpages << hpage_shift);
+ case Opt_min_size:
+ if (!spool || spool->min_hpages == -1)
+ return 0;
+ return sprintf(params->buffer, "min_size=%llu",
+ (unsigned long long)spool->min_hpages << hpage_shift);
+ case Opt_pagesize:
+ hpage_size /= 1024;
+ mod = 'K';
+ if (hpage_size >= 1024) {
+ hpage_size /= 1024;
+ mod = 'M';
+ }
+ return sprintf(params->buffer, "pagesize=%lu%c",
+ hpage_size, mod);
+
+ case Opt_mode:
+ if (sbinfo->mode == 0755)
+ return 0;
+ return sprintf(params->buffer, "mode=%o", sbinfo->mode);
+ case Opt_nr_inodes:
+ if (sbinfo->max_inodes == -1)
+ return 0;
+ return sprintf(params->buffer, "nr_inodes=%lu",
+ sbinfo->max_inodes);
+ default:
+ return -ENODATA;
+ }
+ default:
+ return generic_fsinfo(dentry, params);
+ }
+}
+
static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
@@ -1107,6 +1171,7 @@ static const struct super_operations hugetlbfs_ops = {
.statfs = hugetlbfs_statfs,
.put_super = hugetlbfs_put_super,
.show_options = hugetlbfs_show_options,
+ .get_fsinfo = hugetlbfs_get_fsinfo,
};
/*
diff --git a/fs/kernfs/mount.c b/fs/kernfs/mount.c
index 188c683eab14..b568e6c5e063 100644
--- a/fs/kernfs/mount.c
+++ b/fs/kernfs/mount.c
@@ -17,6 +17,7 @@
#include <linux/namei.h>
#include <linux/seq_file.h>
#include <linux/exportfs.h>
+#include <linux/fsinfo.h>
#include "kernfs-internal.h"
@@ -55,6 +56,20 @@ static int kernfs_sop_show_path(struct seq_file *sf, struct dentry *dentry)
return 0;
}
+static int kernfs_sop_get_fsinfo(struct dentry *dentry, struct fsinfo_kparams *params)
+{
+ struct kernfs_root *root = kernfs_root(kernfs_dentry_node(dentry));
+ struct kernfs_syscall_ops *scops = root->syscall_ops;
+ int ret;
+
+ if (scops && scops->fsinfo) {
+ ret = scops->fsinfo(root, params);
+ if (ret != -EAGAIN)
+ return ret;
+ }
+ return generic_fsinfo(dentry, params);
+}
+
const struct super_operations kernfs_sops = {
.statfs = simple_statfs,
.drop_inode = generic_delete_inode,
@@ -63,6 +78,7 @@ const struct super_operations kernfs_sops = {
.reconfigure = kernfs_sop_reconfigure,
.show_options = kernfs_sop_show_options,
.show_path = kernfs_sop_show_path,
+ .get_fsinfo = kernfs_sop_get_fsinfo,
};
/*
diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h
index 627fa3956146..9fdcdbbb67e9 100644
--- a/include/linux/kernfs.h
+++ b/include/linux/kernfs.h
@@ -25,6 +25,7 @@ struct seq_file;
struct vm_area_struct;
struct super_block;
struct file_system_type;
+struct fsinfo_kparams;
struct kernfs_fs_context;
struct kernfs_open_node;
@@ -170,6 +171,7 @@ struct kernfs_node {
struct kernfs_syscall_ops {
int (*reconfigure)(struct kernfs_root *root, struct fs_context *fc);
int (*show_options)(struct seq_file *sf, struct kernfs_root *root);
+ int (*fsinfo)(struct kernfs_root *root, struct fsinfo_kparams *params);
int (*mkdir)(struct kernfs_node *parent, const char *name,
umode_t mode);
diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c
index fb721aa20aa0..7a12a7876fb3 100644
--- a/kernel/cgroup/cgroup-v1.c
+++ b/kernel/cgroup/cgroup-v1.c
@@ -14,6 +14,7 @@
#include <linux/pid_namespace.h>
#include <linux/cgroupstats.h>
#include <linux/fs_parser.h>
+#include <linux/fsinfo.h>
#include <trace/events/cgroup.h>
@@ -950,6 +951,76 @@ const struct fs_parameter_description cgroup1_fs_parameters = {
.no_source = true,
};
+static int cgroup1_fsinfo(struct kernfs_root *kf_root, struct fsinfo_kparams *params)
+{
+ struct cgroup_root *root = cgroup_root_from_kf(kf_root);
+ struct cgroup_subsys *ss;
+ const char *str = NULL;
+ unsigned int Mth;
+ int ret = 0, ssid;
+
+ switch (params->request) {
+ case FSINFO_ATTR_PARAMETER:
+ if (params->Mth && params->Nth != nr__cgroup1_params)
+ return -ENODATA;
+ switch (params->Nth) {
+ case Opt_all:
+ return 0;
+ case Opt_clone_children:
+ if (test_bit(CGRP_CPUSET_CLONE_CHILDREN, &root->cgrp.flags))
+ str = "clone_children";
+ goto string;
+ case Opt_cpuset_v2_mode:
+ if (root->flags & CGRP_ROOT_CPUSET_V2_MODE)
+ str = "noprefix";
+ goto string;
+ case Opt_name:
+ if (strlen(root->name))
+ return sprintf(params->buffer, "name=%s", root->name);
+ return 0;
+ case Opt_none:
+ return 0;
+ case Opt_noprefix:
+ if (root->flags & CGRP_ROOT_NOPREFIX)
+ str = "noprefix";
+ goto string;
+ case Opt_release_agent:
+ spin_lock(&release_agent_path_lock);
+ if (strlen(root->release_agent_path))
+ ret = sprintf(params->buffer, "release_agent=%s",
+ root->release_agent_path);
+ spin_unlock(&release_agent_path_lock);
+ return ret;
+ case Opt_xattr:
+ if (root->flags & CGRP_ROOT_XATTR)
+ str = "noprefix";
+ goto string;
+ case nr__cgroup1_params:
+ Mth = params->Mth;
+ for_each_subsys(ss, ssid) {
+ if (Mth == 0) {
+ if (root->subsys_mask & (1 << ssid))
+ str = ss->legacy_name;
+ goto string;
+ }
+ Mth--;
+ }
+ return -ENODATA;
+ default:
+ return -ENODATA;
+ }
+
+ default:
+ return -EAGAIN; /* Tell kernfs to call generic_fsinfo() */
+ }
+
+string:
+ if (!str)
+ return 0;
+ strcpy(params->buffer, str);
+ return strlen(params->buffer);
+}
+
int cgroup1_parse_param(struct fs_context *fc, struct fs_parameter *param)
{
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
@@ -1140,6 +1211,7 @@ static int cgroup1_reconfigure(struct kernfs_root *kf_root, struct fs_context *f
struct kernfs_syscall_ops cgroup1_kf_syscall_ops = {
.rename = cgroup1_rename,
.show_options = cgroup1_show_options,
+ .fsinfo = cgroup1_fsinfo,
.reconfigure = cgroup1_reconfigure,
.mkdir = cgroup_mkdir,
.rmdir = cgroup_rmdir,
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index f3238f38d152..15b976003032 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -55,6 +55,7 @@
#include <linux/nsproxy.h>
#include <linux/file.h>
#include <linux/fs_parser.h>
+#include <linux/fsinfo.h>
#include <linux/sched/cputime.h>
#include <net/sock.h>
@@ -1784,6 +1785,35 @@ static int cgroup_show_options(struct seq_file *seq, struct kernfs_root *kf_root
return 0;
}
+static int cgroup_fsinfo(struct kernfs_root *kf_root, struct fsinfo_kparams *params)
+{
+ const char *str = NULL;
+
+ switch (params->request) {
+ case FSINFO_ATTR_PARAMETER:
+ if (params->Mth)
+ return -ENODATA;
+ switch (params->Nth) {
+ case Opt_nsdelegate:
+ if (current->nsproxy->cgroup_ns == &init_cgroup_ns &&
+ cgrp_dfl_root.flags & CGRP_ROOT_NS_DELEGATE)
+ str = "nsdelegate";
+ goto string;
+ default:
+ return -ENODATA;
+ }
+
+ default:
+ return -EAGAIN; /* Tell kernfs to call generic_fsinfo() */
+ }
+
+string:
+ if (!str)
+ return 0;
+ strcpy(params->buffer, str);
+ return strlen(params->buffer);
+}
+
static void apply_cgroup_root_flags(unsigned int root_flags)
{
if (current->nsproxy->cgroup_ns == &init_cgroup_ns) {
@@ -5248,6 +5278,7 @@ int cgroup_rmdir(struct kernfs_node *kn)
static struct kernfs_syscall_ops cgroup_kf_syscall_ops = {
.show_options = cgroup_show_options,
+ .fsinfo = cgroup_fsinfo,
.reconfigure = cgroup_reconfigure,
.mkdir = cgroup_mkdir,
.rmdir = cgroup_rmdir,
diff --git a/samples/Kconfig b/samples/Kconfig
index daa17e9f3197..82625570211a 100644
--- a/samples/Kconfig
+++ b/samples/Kconfig
@@ -148,7 +148,7 @@ config SAMPLE_VFIO_MDEV_MBOCHS
config SAMPLE_STATX
bool "Build example extended-stat using code"
- depends on BROKEN
+ #depends on BROKEN
help
Build example userspace program to use the new extended-stat syscall.
^ permalink raw reply related [flat|nested] 8+ messages in thread